HflMffimmfifflaa 


LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 


Class 


DOMESTIC 

SANITARY    ENGINEERING 
AND    PLUMBING 


DOMESTIC 

SANITARY    ENGINEERING 
AND    PLUMBING 

DEALING  WITH  DOMESTIC  WATER  SUPPLIES, 
PUMP  &  HYDRAULIC  RAM  WORK,  HYDRAULICS, 
SANITARY  WORK,  HEATING  BY  LOW  PRESSURE, 
HOT  WATER,  &  EXTERNAL  PLUMBING  WORK 


BY 


F.     W.     RAYNES,    R.P. 

MEDALLIST,    CITY    AND    GUILDS    OF    LONDON    INSTITUTE 

HEAD  OF   THE   PLUMBING   DEPARTMENT,   AND 

ASSISTANT    LECTURER     IN     THE     DEPARTMENT    OF    CIVIL     ENGINEERING 
THE   GLASGOW   AND   WEST  OF   SCOTLAND   TECHNICAL  COLLEGE,   GLASGOW 


WITH  277  ILLUSTRATIONS 


LONGMANS;  GREEN,   AND   co. 

39    PATERNOSTER    ROW,    LONDON 

NEW    YORK,   BOMBAY,   AND    CALCUTTA 

1909 

All  rights  reserved 


o 


PREFACE 

IN  order  to  cover  the  subject  without  making  the  book 
unwieldy,  and  expensive  to  procure,  it  has  been  necessary 
to  omit  a  great  deal  of  elementary  and  general  matter,  and 
instead  of  devoting  space  to  the  Municipal  side  of  Sanitary 
Engineering  the  scope  of  the  work  has  been  limited  to  the 
title  of  the  book. 

Many  formulae  have  been  introduced  as  an  aid  in  the 
design  of  work,  and  in  most  cases  these  have  been  given 
in  as  simple  a  form  as  possible  consistent  with  accuracy, 
whilst  numerous  examples  have  been  worked  to  show  their 
application. 

Although  the  book  will  be  found  valuable  for  Students  of 
Domestic  Sanitary  Engineering  and  Plumbing  for  Examination 
purposes,  the  writer  hopes  that  it  will  have  a  still  greater 
value  for  those  who  are  entrusted  with  the  design,  the 
supervision,  and  the  execution  of  this  branch  of  engineering 
work. 

Much  time  has  been  entailed  in  the  preparation  of  suitable 
drawings,  and  where  a  catalogue  illustration  has  been  used, 
it  is  not  intended  to  convey  that  a  certain  manufacturer's 
goods  are  superior  to  those  of  another  firm,  but  to  illustrate 
some  principle  or  point  under  discussion. 

For  valuable  aid  in  the  preparation  of  the  illustrations 
the  writer's  thanks  are  due  to  his  drawing  assistant,  Mr. 
John  Burnside. 

F.  W.  RAYNES. 

THE  GLASGOW  AND  WEST  OF  SCOTLAND 
TECHNICAL  COLLEGE,  GLASGOW. 


195099 


CONTENTS 


CHAPTER   I 

MATERIALS  AND  THEIR  PROPERTIES :  MODE  OF 
MANUFACTURE 

riai 

Metals — Physical  and  chemical  properties — Lead  ores — Reduction  of 
ores — Lead  compounds — Lead  pipes — Tinned  lead  pipes — Tin-lined 
lead  pipe— Lead  traps  and  bends— Cast  sheet  lead— Milled  lead — Iron 
ores — Wrought  iron — Steel — Malleable  cast  iron — Iron  pipes — 
Coatings  for  pipes — Copper — Coatings  for  copper — Sheet  copper — 
Copper  tubes — Tin — Block  tin  tube — Zinc — Alloys — Properties 
of  alloys — Composition — Sanitary  pottery — Fireclay — Earthenware 
drain  pipes — Concrete  tubes  .....  1-29 


CHAPTER  II 
ROOF  WORK 

Metal  Coverings — Lead  flats  or  platforms — Solid  rolls — Roll  ends — 
Soldered  dots — Hollow  rolls — Intersecting  rolls — Lead  gutters — Drips 
— Drip-boxes  or  cesspools — Soakers — Cover  flashings — Gutter  flash- 
ings— Step  flashings — Dormers — Glass  roof  and  skylights — Cornices 
— Stone  copings — Hips  and  ridges — Methods  of  securing  leadwork — 
Ornamental  ridging — Torus  rolls — Turret  roofs — Shape  of  bays — 
Domes — Finials — Strengths  of  lead  ....  30-80 


CHAPTER  III 
PIPE  FIXING  AND  PIPE  BENDING 

Methods  of  supporting  pipes— Wood  grounds — Plain  tacks — Ornamental 
lugs  or  tacks — Ornamental  fixings— Flange  supports— Pipe  hangers 
— Special  wall  clips — Roller  fixings — Bending  lead  pipes — Springs 
— Weights — Dummies — Working  drawings — Development  of  elbow 
pipes— Bending  copper  pipes — Bending  machines  .  .  81-96 

vii 


Vlll  CONTENTS 

CHAPTER   IV 
PIPE  JOINTS 

PAGE 

Joints  for  lead  pipes — Preparation  of  joints — Gauges — Methods  of  support- 
ing joints — Joints  for  tin-lined  lead  pipes — Burnt  joints — Joints  for 
copper  pipes — Iron  pipe  joints — Lead  wool — Expansion  joints — Pack- 
ing rings — Expansion  bends — Joints  for  w.c.'s — Joints  for  drains — 
Patent  joints— Elastic  cement  .....  97-123 

CHAPTER  V 
SOLDERS,  FLUXES,  AND  LEAD  BURNING 

Soft  solders — Composition  and  fusing  points — Properties  of  solder — Treat- 
ment of  poisoned  solder — Hard  or  brazing  solders — Composition  of 
hard  solders — Fluxes,  and  their  use — Lead  burning — Hydrogen 
generator — Method  of  charging  generator — Tank  for  supply- 
ing atmospheric  air — Compressed  gases  in  cylinders — Cost  of 
oxygen  ........  124-135 

CHAPTER   VI 
SANITARY  FITTINGS  AND  ACCESSORIES 

Principles  governing  construction — Water-closets — Wash-out  type— Wash- 
down  type — Flush  pipes — Combination  closets — Valve  closets,  merits 
and  defects — Siphonic  closets,  types,  their  action  and  limitations 
— Trough  closets — Siphonic  latrines — Ranges  of  closets — Connec- 
tions of  w.c.'s — Flushing  cisterns,  types  in  use — Waste  water 
preventers,  mechanical  and  pneumatic  types — Lavatories,  their 
merits  and  defects — Baths,  treatment  of  overflows — Sinks — Wash- 
tubs — Slop  sinks — Urinals,  forms  they  take,  their  merits  and 
defects  .  V  .  .  .  .  .A  136-166 

CHAPTER  VII 
SOIL  AND  WASTE  PIPES 

Materials — Iron  soil  pipes — Copper  soil  pipes — Thickness  of  soil  pipes — 
Arrangement  of  soil  pipes — Sizes  of  soil  pipes — Sizes  of  antisiphon- 
age  pipes — Effect  of  arrangement  of  pipes  on  sizes  of  antisiphonage 
pipes — Unsealing  of  traps,  cause  and  prevention — Waste  pipes — 
Sizes  of  waste  pipes — Arrangement  of  waste  pipes — Rust  pockets 
— Traps  for  waste  pipes  ......  167-192 


CONTENTS  IX 

CHAPTER   VIII 
DRAINAGE  OF  HOUSES  AND  OTHER  BUILDINGS 

PAGE 

General  design — Merits  and  drawbacks  of  earthenware  and  of  iron  drains 
— Foundations  for  drains — Connections  with  drains — Junctions  and 
bends — Chambers  and   openings    for    access — Sizes  of   chambers — 
Manhole  covers — Gully  traps — Disconnecting  traps — Grease  traps — 
Tidal   traps — Drainage  of   basements    and  sewage   lifts — Drainage 
plans — Stable  drainage — Connections  of  drains  with  sewers — Venti- 
lating and  flushing  of  drains — Automatic  flush  tanks — Methods  of 
laying  drains — Boning  rods  and  sight  rails — Timbering  trenches — 
Drain   testing — Testing    appliances — Discharging  capacity  of  drains 
— Hydraulic  mean  depth — Velocity  formula         .  .  .     193-242 

CHAPTER  IX 

DISPOSAL  AND  TREATMENT  OF  SEWAGE  FROM  MANSIONS 
AND  HOUSES  IN  COUNTRY  DISTRICTS 

Methods  of  treatment — System  of  subsoil  irrigation,  sizes  of  tanks, 
amount  of  land  required — Sewage  filters — Difference  between  contact 
beds  and  percolating  filters  .....  243-250 

CHAPTER  X 
WATER  SUPPLY 

Water  pollution — Sources  of  supply — Collecting  area — Special  collecting 
surfaces — Conditions  affecting  yield  by  a  surface — Rainfall — Volume 
of  water  available — Capacity  of  storage  tanks — Water  consumpt — 
Rain-water  separators — Sand  filters — Surface  springs — Deep  springs — 
Wells  as  a  source  of  supply — Boreholes — Hardness  of  water — Soften- 
ing water — Water  services,  constant  and  intermittent  supplies- 
Arrangement  of  service  pipes — Connections  of  service  pipes  with 
street  mains — Storage  cisterns — Cistern  overflows  and  washouts — 
Sizes  and  capacities  of  tanks — Domestic  filters — Ball-cocks — Screw- 
down  and  plug  cocks — Spring  or  semi-automatic  taps — Water- 
hammer  in  pipes,  cause  and  remedy  ....  251-307 

CHAPTER   XI 

APPLIANCES  FOR  RAISING  WATER 

Lift  pump — Suction  pipes — Deep  well  pumps — Lift  and  force  pumps — Air 
vessels— Double  barrelled  pumps— Formulae  for  lift  pumps— Formulae 
for  lift  and  force  pumps — Geared  pumps— Formula  for  geared  pumps — 
Hydraulic  rams — Long  and  short  drive  pipes — Air  vessels  for  rams — 
Duty  of  rams — Formulae  for  rams— Ram  pumps  and  their  action  308-339 


X  CONTENTS 

CHAPTER   XII 

HYDROSTATICS  AND  HYDRAULICS 

PAGE 

Pressure  due  to  head  of  water — Total  pressure — Resistance  to  the  flow  of 
water — Vena  contracla — Flow  of  water  through  orifices  and  short 
tubes — Flow  of  water  through  long  pipes — Hydraulic  gradient — 
Sizes  of  pipes — Head  absorbed  by  friction — Thickness  and  strength 
of  pipes  ........  340-365 

CHAPTER   XIII 
DOMESTIC  HOT  WATER  SUPPLY 

Movement  of  heat — Circulation  of  water — Tank  system — Cylinder  system 
— Details  of  systems — Secondary  circuits — Cylinder-tank  systems, 
merits  and  defects — Sizes  of  tanks — Range  and  independent  boilers — 
Duty  of  range  boilers — Formula}  for  range  and  dome  top  independent 
boilers — Steam  apparatus  for  heating  water— Properties  of  steam — 
Boiling  point — Automatic  steam  supply  valves — Steam  traps — Heat 
transmitted  by  steam  coils — Indirect  hot-water  systems  for  preventing 
incrustation  difficulties — Forms  of  indirect  heaters — Collapse  of 
cylinders,  and  its  prevention — Noises  in  boilers — Boiler  explosions — 
Safety  valves  .  .  .  .  .  .  .  366-426 

CHAPTER  XIV 
LOW  PRESSURE  HOT- WATER  HEATING  APPARATUS 

Systems  of  piping — Pitch  of  pipes — Circulating  head — Sizes  of  pipes — 
Heating  surfaces— Comparative  value  of  heating  surfaces — Radiator 
valves — Air  valves — Feed  cisterns — Calculations  of  heating  surface — 
Discharge  of  air  through  flues — Heat  to  warm  air — Heat  absorbed  by 
wall  and  glass  surfaces — Heat  emitted  by  pipe  surfaces — Drying 
rooms — Boilers  for  low  pressure  heating — Value  of  direct  and  indirect 
surfaces — Boiler  draught  regulator — Sizes  of  boilers — Calorific  value 
of  fuels— Size  of  chimneys  .....  427-466 

APPENDIX 

Hydraulic  memoranda — Weight  of  water  at  different  temperatures — 
Weight  of  metals — Weight  of  cast-iron  pipes — Wire  and  plate 
gauges  ........  462-466 


CONTENTS  xi 


WORKED  EXAMPLES. 

HOUSE  DRAINAGE 
NO.  PAGE 

1.  Hydraulic  mean  depth  of  a  6-inch  pipe  when  water  is  flowing  J  the 

depth  of  pipe  .  .  .  .  .  .  .     238 

2.  Gradients  which  produce  velocities  of  3  feet  per  second  in  a  6-inch 

pipe  when  the  latter  is  flowing  £  and  £  full ....     240 

3.  Discharging  capacity  of  a  6 -inch  drain  when  flowing  f  full,  and  when 

laid  with  a  gradient  of  1  in  50          .  .  .  .  .     242 


WATER  SUPPLY 

4.  Volume  of  rainfall  available  from  a  given  surface        .  .  .258 

5.  Collecting  area  required  to  yield  a  given  volume  of  water        .             .  258 

6.  To  determine  width  of  a  storage  tank  .....  260 

7.  Depth  of  circular  storage  tank  required  when  other  particulars  are 

given             ........  260 

8.  Diameter  of  tank  required  for  given  conditions            .             .            .  260 

9.  Capacity  of  irregular  shaped  tank         .....  291 
10.  Depth  of  irregular  shaped  tank  when  other  particulars  are  given         .  291 


APPLIANCES  FOR  RAISING  WATER 

11.  Volume  of  water  raised  by  a  3J-inch  diameter  lift  pump  in  a  given 

time  .......'.     320 

12.  Diameter  of  lever  pump  to  raise  a  given  volume  of  water  in  a  given 

time  .........     321 

13.  Force  required  to  be  exerted  at  the  end  of  a  lever  to  overcome  a  given 

load  ........  .     322 

14.  Effort  necessary  to  raise  water  by  means  of  a  4-inch  diameter  lift 

pump  ........     323 

15.  To  determine  diameter  of  a  lift  and  force  pump  when  worked  with 

limited  power  .......     325 

16.  Effort  necessary  to  raise  water  through  a  given  height  by  means  of  a 

lift  and  force  pump  .......     325 

17.  Volume  of  water  raised  by  a  lift  and  force  pump          .  .  .     325 

18.  Effort  necessary  to  raise  water  through  a  given  height  by  a  wheel- 

handle  lift  and  force  pump   ......     328 

19.  To  determine  diameter  of  a  geared  wheel-handle  pump  for  working 

with  limited  power  .......  328 

20.  Volume  of  water  raised  by  a  geared  double  barrelled  pump      .             .  329 

21.  Volume  of  water  raised  by  a  hydraulic  ram     ....  336 

22.  Water  supplied  to  ram  in  any  given  time        ....  336 

23.  To  determine  efficiency  of  a  hydraulic  ram      ....  336 


Xll  CONTENTS 


HYDROSTATICS  AND  HYDRAULICS 
NO.  PAGE 

24.  Total  pressure,  and  the  average  pressure  per  sq.  inch  on  a  vertical 

surface  of  a  cylindrical  tank .             .             .             .             .            .  342 

25.  Total  pressure  acting  upon  a  circular  stopper  ....  343 

26.  Total  pressure  acting  upon  one  side  of  a  rectangular  cistern    .             .  343 

27.  Head  of  a  column  of  water  equivalent  to  a  given  load  on  a  safety 

valve              ........  343 

28.  Discharge  of  water  by  a  short  tube        .....  346 

29.  Head  absorbed  by  friction  in  discharging  a  given  volume  of  water 

through  a  short  tube  .  .  .  .  .  .347 

30.  Discharging  capacity  of  a  cast-iron  pipe            ....  349 

31.  Diameter  of  pipe  necessary  to  discharge  a  given  volume  with  given 

head  .  .  .-'  .  .  .  .  .  .350 

32.  Sizes  of  pipes  for  a  compound  main       .....  352 

33.  Volume  discharged  by  a  tap  when  subjected  to  a  given  head,  and 

where  length  of  pipe  is  comparatively  short             .         •'.,'•         .  355 

34.  Discharging  capacity  of  a  given  arrangement  and  size  of  pipe  .             .  357 

35.  Diameter  of  pipe  necessary  for  a  given  discharge          .            .            .  358 

36.  Sizes  of  main  draw-off  pipe  and  branches,  when  the  latter  are  dis- 

charging simultaneously  given  volumes  of  water     .             .            .  360 

37.  Maximum  safe  working  pressure  for  a  lead  pipe           .             .             .  364 

38.  Thickness  of  lead  pipe  .  .  .  .  .  .  .365 

39.  Thickness  of  a  cast-iron  pipe  required  when  subjected  to  a  given 

water  pressure            ....            ....           -.             .  365 

DOMESTIC  HOT  WATER  SUPPLY 

40.  Volume  of  water  heated  by  a  given  type  of  range  boiler           .             .  395 

41.  Volume  of  water  heated  by  a  given  type  of  range  boiler           .             .  395 

42.  Volume  of  water  heated  by  a  given  type  of  range  boiler           .             .  395 

43.  Time  required  to  heat  a  given  volume  of  water  by  a  range  boiler         .  396 

44.  Heating  capacity  of  a  dome  top  independent  boiler      .            .            .  397 

45.  Size  of  independent  boiler  necessary  to  do  a  specific  amount  of  work  .  397 

46.  Volume  of  hot  water  essential  to  produce  a  larger  volume  at  a  given 

lower  temperature  and  capacity  of  hot-water  tank  .         .-•  .,            .  399 

47.  Capacity  of  a  cylindrical  tank  .             .             »             .,           .             .  400 

48.  Height  of  a  cylindrical  tank  when  capacity  and  diameter  are  given     .  400 

49.  Diameter  of  a  cylindrical  tank  when  its  capacity  and  height  are  given  .  400 

50.  Length  of  steam  heated  coil  essential  to  raise  water  through  a  given 

temperature  .  .  .  .  .  .  .  .411 

51.  Gallons  of  water  raised  by  a  steam  heater  in  a  given  time       .  .412 

52.  Time  required  for  a  steam  heater  to  do  a  specific  amount  of  work        .  412 


Low  PRESSURE  HOT- WATER  HEATIJSLG  APRARATUS 

53.  Discharging  capacity  of  an  air  duct  per  hour    ....     444 

54.  Heating  surface  necessary  to  warm  a  room  to  a  given  temperature      .     448 


CONTENTS  Xlll 

NO.  PAGE 

55.  Heating  surface  necessary  to  warm  a  room  to  a  given  temperature      .  449 

56.  Heating  surface  for  drying  room           .....  450 

57.  Size  of  cast-iron  sectional  boiler  for  a  given  amount  of  work    .             .  460 

58.  Heating  capacity  of  a  given  size  and  type  of  boiler      .             .            .  460 

59.  Size  of  chimney  required  for  heating  boiler      ....  461 


TABLES 

I.  Strengths  of  lead  for  roof  work      .  .  .  .  .80 

II.  Capacity  of  tanks  and  size  of  siphons  for  flushing  drains  .             .  223 

III.  Data  for  obtaining  hydraulic  mean  depth  and  the  sectional  area 

of  flow  in  circular  drains,  when  water  is  running  at  different 
depths    .  .  "    .  .  .  .  .239 

IV.  Values  of  c  for  Kutter's  formula     .....  240 
V.  Approximate  gradients  for  drains  .....  242 

VI.  Efficiency  values  for  hydraulic  rams           ....  336 

VII.  Sizes  of  drive  and  delivery  pipes  for  hydraulic  rams          .             .  337 

VIII.  Coefficients  for  hydraulic  formula  .....  348 

IX.  5th  power  of  pipe  diameters            .....  348 

X.  Coefficients  for  formula  in  connection  with  short  pipes  and  fittings  354 

XL  Average  tensile  strength  of  metals              ....  363 

XII.  Constants  or  coefficients  for  different  forms  of  range  boilers          .  394 

XIII.  Properties  of  steam             ......  403 

XIV.  Heat  transmitted  by  short  steam-heated  coils        .            .             .  411 
XV.  Boiling  point  of  water  when  subjected  to  different  pressure  heads  416 

XVI.  Approximate  heating  surface  supplied  by  various  sizes  of  pipes 

(low  pressure  hot-water  heating)            .  435 

XVII.  Heat  lost  through  brick  walls  in  British  units      .            .             .  445 

XVIII.  Heat  lost  through  stone  walls  in  British  units       .             .             .  446 

XIX.  Heat  lost  by  glass  and  other  surfaces  in  British  units        .             .  446 

XX.  Heat  transmitted  by  horizontal  pipe  surfaces        .             .             .  447 

XXL  Approximate  space  warmed  by  a  square  foot  of  heating  surface    .  451 

XXII.  Calorific  value  of  fuels        .  .  .  .  .  .458 

XXIII.  Coefficients  for  various  forms  of  hot  water  heaters  and  different 

rates  of  firing     .            .            .            .             .            .             .  459 


DOMESTIC    SANITARY 
ENGINEERING    AND    PLUMBING 

CHAPTEE    I 

MATERIALS    AND   THEIR   PROPERTIES:    MODE   OF 
MANUFACTURE 

A  GOOD  knowledge  of  the  properties  of  materials  is  essential 
for  executing  work  of  importance  where  durability  and  sound 
workmanship  are  required.  From  time  to  time  much  work 
has  resulted  in  failure  owing  to  ignorance  of  the  properties  of 
the  materials  employed. 

Metals. — The  properties  of  metals  are  both  physical  and 
chemical.  Physical  properties  are  malleability,  fusibility, 
ductility,  tenacity,  flow  of  metals,  lustre,  elasticity,  electric 
conductivity,  and  heat  conductivity. 

Malleability  is  that  property  which  permits  of  a  metal 
being  rolled  into  sheets,  and  worked  into  various  shapes, 
without  the  metal  being  broken  or  torn. 

Fusibility,  as  the  term  indicates,  is  the  conversion  of  a 
solid  into  the  liquid  state  by  the  application  of  sufficient 
heat.  All  metals,  with  the  exception  of  mercury,  are  solid 
at  normal  temperatures. 

Ductility  is  the  property  which  permits  a  metal  to  be 
drawn  into  the  form  of  wire ;  the  thinner  the  wire  can  be 
drawn  the  more  ductile  is  the  metal. 

Density  is  the  relative  weight  of  a  body  when  compared 
with  an  equal  volume  of  water.  All  the  metals  used  in 
Plumbers'  Work  are  heavier  than  water.  Lead  is  the  heaviest, 
having  a  density  or  specific  gravity  of  1 1  '4  ;  whilst  aluminium 


2       DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

is  the  lightest,  having  a  density  of  2 '6  7.  In  other  words, 
volume  for  volume  lead  is  11*4  times  heavier  than  water,  and 
aluminium  2*6*7  times  heavier. 

Tenacity  indicates  that  property  which  resists  the 
particles  or  molecules  of  which  a  body  is  composed  from 
being  torn  asunder.  The  tenacity  of  metals  is  greatly  re- 
duced when  they  are  subjected  to  high  temperatures. 

Flow  of  Metals. — Although  not  visible  to  the  naked 
eye,  the  molecules  composing  metals  are,  to  a  more  or  less 
extent,  in  a  state  of  motion  due  to  variations  of  temperature. 
Flow  of  metals  is  more  pronounced  when  they  are  subjected 
to  pressure ;  thus  a  piece  of  sheet  lead  can  be  thinned  in 
one  place  and  thickened  in  another,  owing  to  the  manner  in 
which  the  molecules  can  be  displaced  by  the  application  of 
the  bossing  stick  or  mallet.  In  other  words,  the  metal  is 
said  to  flow.  It  is  on  account  of  this  property  that  a  block 
of  lead  can  be  rolled  into  thin  sheets,  or  forced  through  a 
die  to  take  the  form  of  a  pipe. 

Lustre. — All  metals  when  clean  or  when  polished  reflect 
light,  and  therefore  have  a  high  lustre. 

Elasticity  is  that  property  which  permits  of  a  metal 
regaining  after  distortion  its  original  shape.  Thus  if  a  steel 
bar  is  only  bent  or  elongated  by  the  application  of  force, 
the  bar  will  regain  its  normal  state  when  the  force  is 
removed,  provided  the  elastic  limit  of  the  metal  has  not 
been  exceeded.  When  the  elastic  limit  has  been  passed  a 
permanent  set  is  made. 

Conductivity. — Metals  are  good  conductors  of  both  heat 
and  electricity,  although  some  are  much  better  than  others. 
Copper  ranks  as  the  best  conductor  of  the  common  metals 
for  either  heat  or  electricity,  whilst  lead  is  about  the  worst. 

Chemical  Properties. — When  in  the  molten  state  the 
common  metals  have  a  great  affinity  for  oxygen,  with  the 
result  that  oxides  of  these  metals  are  rapidly  produced. 
Dry  air  does  not  affect  metals  at  normal  temperatures  to 
any  considerable  extent,  but  when  the  air  is  moist,  and 
carbonic  acid  is  present,  the  surfaces  of  metals  are  readily 
attacked  and  covered  with  a  film  of  oxide. 

Acids,  such  as  Nitric,  Hydrochloric,  and  Sulphuric,  tend 


MATERIALS    AND    THEIR    PROPERTIES  3 

to  dissolve  the  common  metals  to  a  more  or  less  extent. 
Sulphuric  acid  when  cold  only  slowly  affects  lead,  owing  to 
sulphate  of  lead  forming  on  the  surfaces  and  acting  as  a 
protective  covering  for  the  metal  beneath. 

Lead  and  its  Ores. — The  ores  which  are  capable  of 
yielding  considerable  quantities  of  metallic  lead  are  Galena 
and  Cerusite.  The  former  is  a  dark-coloured,  metallic 
looking  substance,  and  is  the  most  widely  distributed. 
Cerusite  occurs  as  a  carbonate  of  lead  in  the  form  of 
a  white  or  dark  earthy  substance,  and  intermixed  with 
clay  and  limestone,  etc. ;  galena  is  also  often  present  in 
its  admixture.  Galena  (PbS)  is  a  compound  consisting 
principally  of  lead  and  sulphur,  and  when  this  ore  is 
placed  in  the  smelting  furnace  it  contains  from  70  to  85 
per  cent,  of  lead.  Cerusite  (PbC03),  or  white  lead  ore,  is 
a  compound  consisting  chiefly  of  lead,  oxygen,  and  carbonic 
acid  gas.  The  pure  ore  will  yield  as  much  as  77J  per  cent, 
of  lead,  whilst  the  crude  ore  contains  about  30  per  cent,  of 
lead.  Although  galena  is  very  widely  distributed,  it  does 
not  occur  in  many  places  in  sufficient  quantity  to  pay  for 
working  it.  The  principal  British  localities  where  lead  is 
obtained  are  North  Wales,  Derbyshire,  Cornwall,  Northum- 
berland, Lanarkshire,  and  Laxey,  Isle  of  Man.  Large 
quantities  of  lead  are  imported  to  Great  Britain  from 
Spain.  Cerusite  is  found  in  large  deposits  in  Nevada  and 
in  Colorado,  U.S.,  and  it  also  occurs  in  Scotland,  principally 
at  the  Lead  Hills,  Lanarkshire.  The  lead  of  commerce, 
however,  is  obtained  usually  from  galena. 

Reduction  of  Ores. — Lead  is  extracted  from  the  ore  in 
smelting  furnaces,  which  differ  in  operation  and  construction 
in  different  localities,  and  according  to  the  nature  of  the 
impurities  in  the  ore.  The  impurities  lead  contains  are 
silver,  iron,  zinc,  antimony,  and  copper,  etc.,  and  these 
render  the  lead  very  hard.  All  the  impurities,  with  the 
exception  of  silver,  can  be  removed  by  raising  the  lead  to 
a  high  temperature  in  the  presence  of  air,  when  oxidation 
of  the  impurities  takes  place  at  the  surface  and  they  can 
be  taken  off  in  the  form  of  a  scum.  To  extract  the  silver, 
the  lead  is  subjected  to  either  the  Pattinson  or  Parkes 


4      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

process.  The  object  aimed  at  in  each  process,  is  to  con- 
centrate the  silver  into  a  small  quantity  of  lead,  when  the 
rich  argentiferous  lead  is  afterwards  finally  freed  from  the 
silver  by  cupellation.  A  little  impurity  in  lead,  however, 
is  not  always  objectionable.  In  the  case  of  sheet  lead  for 
roof  work,  and  where  it  requires  to  be  worked  into  various 
shapes,  the  metal  should  be  as  free  from  impurity  as 
possible.  Soil  pipes  which  require  bends  made  in  them 
should  also  be  of  soft  lead.  Lead  water  pipes,  on  the  other 
hand,  and  which  deliver  water  under  more  or  less  considerable 
pressure,  are  better  made  of  lead  which  contains  a  little 
impurity.  In  this  case  the  harder  pipes  better  resist  the 
erosive  action  of  water  when  flowing  through  them  at  high 
velocities.  Thick  sheet  lead  and  plate  lead,  which  is  used 
for  lining  vitriol  tanks,  is  said  to  better  resist  the  action 
of  the  acid  when  it  contains  a  small  percentage  of  antimony. 

Physical  Properties  of  Lead. — In  colour  lead  is  bluish- 
gray,  and  when  newly  cut  has  a  bright  metallic  lustre,  but 
is  rapidly  oxidised  in  the  presence  of  moist  air.  Lead 
is  not  very  ductile,  so  it  cannot  be  drawn  into  very  thin 
wire ;  it  has  a  low  tenacity,  and  is  useless  where  strength  or 
toughness  is  required.  The  specific  gravity  of  lead  is  about 
11*4,  and  a  cubic  foot  weighs  approximately  712  Ib.  It  is 
not  a  perfectly  elastic  metal,  and  the  rate  of  expansion 
slightly  exceeds  that  of  contraction.  The  latter  property 
is  noticeable  in  many  lead-lined  sinks,  where  the  metal  has 
formed  itself  into  ridges  or  buckles  owing  to  its  size  being 
intermittently  increased.  Many  lead  pipes  are  either 
distorted  or  fractured  by  increase  of  length  due  to  alternate 
heating  and  cooling.  Lead  is  a  poor  conductor  of  heat  and 
electricity,  but  it  is  very  malleable  and  soft,  and  can  be  readily 
worked  into  various  shapes  without  the  application  of  heat. 

Chemical  Properties  of  Lead. — To  a  more  or  less  extent 
lead  is  acted  upon  by  all  acids,  and  also  by  moist  air.  After 
lead  has  been  newly  laid  in  gutters,  or  fixed  in  connection 
with  other  roof  work,  it  is  generally  found  that  on  the  follow- 
ing day  the  surfaces  of  the  lead  are  covered  with  a  thin 
film  of  basic  carbonate  of  lead ;  this  film  is  due  to  the 
moisture  and  carbonic  acid  gas  in  the  atmosphere  acting 


MATERIALS    AND    THEIR    PROPERTIES  5 

upon  the  lead.  The  action  readily  takes  place  after  sunset 
when  dew  is  deposited,  or  in  the  daytime  when  the  atmo- 
sphere is  in  a  saturated  state.  Sheet  lead  work  always  has 
a  better  appearance  a  day  or  two  after  it  has  been  done, 
owing  to  the  carbonate  film  producing  a  dull  surface  and 
obscuring  tool  marks. 

Water,  when  pure,  is  said  to  have  no  action  upon  lead, 
but  when  it  contains  free  oxygen  the  lead  is  attacked,  forming 
an  oxide  which  is  soluble  in  water.  If  carbonic  acid  gas 
is  also  present  in  the  water,  the  dissolved  oxide  is  precipitated 
as  basic  carbonate,  and  the  surfaces  of  the  lead  are  again 
laid  bare  to  the  action  of  the  water.  Impurities  in  water 
act  differently ;  some  tend  to  prevent  water  acting  upon 
lead,  whilst  other  impurities  tend  to  accelerate  the  action. 

Sulphuric  acid,  when  dilute,  has  no  action  upon  lead ; 
strong  solutions  of  the  acid  at  ordinary  temperatures  act 
slowly  upon  it,  but  the  action  is  accelerated  by  the  concen- 
tration of  the  acid  and  with  rise  of  temperature.  Boiling 
sulphuric  acid  readily  converts  the  lead  into  a  sulphate 
with  the  evolution  of  sulphurous  acid.  Lead  is  readily  dis- 
solved by  dilute  nitric  acid,  and  it  is  also  acted  upon  by 
hydrochloric  acid. 

Lead  Compounds. — The  principal  lead  compounds,  so  far 
as  plumbers  are  directly  concerned,  are  red  lead  and  white  lead  ; 
the  former  is  an  oxide  of  lead,  whilst  the  latter  is  a  carbonate 
of  lead.  These  two  compounds  are  largely  used  by  plumbers 
for  jointing  materials. 

Red  Lead. —  (Pb304)  is  made  by  exposing  molten  lead  in 
a  furnace  to  the  action  of  the  air ;  as  oxidation  takes  place 
the  metallic  surfaces  are  repeatedly  renewed  by  pushing  the 
oxide  towards  the  back  of  the  furnace,  this  operation  being 
continued  until  apparently  the  whole  of  the  metallic  lead  is 
converted  into  an  oxide.  It  is  then  removed  from  the 
furnace  to  the  grinding  mill,  where  it  is  ground  in  water  with 
heavy,  revolving  stone  rollers.  The  grinding  process,  besides 
reducing  the  oxide  into  a  fine  state  of  division,  separates  the 
oxidised  from  any  metallic  lead  which  may  be  present. 
After  leaving  the  grinding  mill  the  oxidised  lead  is  put  into 
a  furnace  which  is  called  the  colouring  oven,  and  which  has 


6       DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

a  temperature  of  about  600°  F.  In  this  oven  the  oxide  is 
exposed  to  the  action  of  the  air  for  about  twenty-four  hours, 
in  order  that  it  may  take  up  a  further  amount  of  oxygen, 
which  is  absorbed  at  a  gradually  decreasing  rate  until  oxida- 
tion is  complete,  and  the  oxide  has  assumed  a  bright  red 
colour.  The  red  lead  is  now  removed  from  the  colouring 
oven  and  reground  in  water,  and  afterwards  dried. 

Litharge  (PbO)  is  made  precisely  in  the  same  manner  as 
red  lead,  excepting  that  the  furnaces  are  raised  to  a  higher 
temperature.  Litharge  is  yellow  in  colour. 

The  difference  in  colour  of  red  lead  and  litharge  is  due  to 
the  different  amounts  of  oxygen  which  have  entered  into  their 
compositions. 

White  Lead  (PbC03)  is  made  in  different  ways,  but  the 
Dutch  process  is  the  one  best  known.      In  the  Dutch  process 
either  specially  cast  grids  of  lead,  or  sheet  lead  loosely  formed 
into  coils,  are  placed  in  jars  which  contain  acetic,  acid.     The 
lead  is  fixed  clear  of  the  acid,  and  the  jars  are  arranged  in 
rows  and  built  up  in  stacks.     At  the  bottom  of  the  stack  a 
thick  layer  of  fermenting  material,  such  as  tan,  is  placed,  and 
upon  this  the  jars  are  arranged  side  by  side,  and  surrounded 
with  the  same  material.      Over  the  mouths  of  the  jars  thin 
lead  plates  are  fixed,  and  then  another  floor  is  formed  by 
laying  boards  on  the  top  of  the  jars.      On  this  floor  another 
layer  of  tan  is  placed,  and  other  jars  are  arranged  as  above 
described.      The  jars  are  built  up  in  tiers  in  this  way  until 
the  stack  is  sufficiently  high.     When  complete,  the  stack  is 
left  for  about  three  months,  during  which  time  fermentation 
takes  place,  and  the  whole  mass  becomes  thoroughly  heated. 
The  heat  generated  in  the  stack  vaporises  the  acetic  acid,  and 
as  the  vapour  combines  with  the  carbonic  acid  gas  given  off 
by  the  decomposing  tan,  the  metallic  lead  is  attacked  and 
converted  into  a  basic  carbonate  of  lead.      In  clue  time  the 
corroded  lead  is  removed  from  the  jars,  and  freed  from  any 
metallic  lead  by  passing  it  between  corrugated  rollers.     The 
grinding  process  is  the  next  operation,  and  if    the    lead  is 
required  in  the  form  of  paste  it  is  reground  in  linseed  oil. 

Lead  Pipes. — For  purposes  of  comparison  lead  pipes  may 
be  divided  into  four  classes,  viz :  First,  ordinary  lead  pipes ; 


MATERIALS    AND   THEIR    PROPERTIES  7 

second,  lead  pipes  which  have  one  or  both  surfaces  tinned ; 
third,  tin-lined  lead  pipes  where  the  tin  and  lead  are  in 
contact ;  and  fourth,  tin-lined  lead  pipes  where  the  tin  and 
lead  are  separated  by  a  covering  of  asbestos  or  similar 
material. 

Lead  pipes  are  made  by  the  aid  of  the  hydraulic  pipe 
press,  hand-made  pipes  being  now  a  thing  of  the  past.  The 
manufacture  of  lead  pipes  is  apparently  a  simple  process, 
but  great  care  is  required  when  setting  the  die  and  core 
of  a  machine,  in  order  that  a  pipe  will  be  turned  out  as 
nearly  true  in  section  as  possible. 

In  Fig.  1  a  lead  pipe  making  machine  is  given.  Its 
principal  parts  are  the  ram  P,  container  C,  the  core  or 
mandril  M,  and  the  die  D.  Molten  lead  is  run  into  the 
container  C  until  the  latter  is  filled  and,  as  a  rule,  holds  just 
sufficient  lead  to  make  two  bundles  of  half-inch  pipe.  The 
lead  is  allowed  to  solidify,  but  whilst  still  hot  hydraulic 
pressure  is  brought  to  bear  upon  the  ram  P,  and  to  raise  the 
piston.  From  the  rising  container  the  lead  only  has  one  point 
of  escape,  and  that  is  through  the  annular  space  between  the 
mandril  and  the  die.  Through  this  space  the  lead  issues  in 
the  form  of  a  pipe.  The  die  D,  it  will  be  observed,  forms 
the  external  diameter  of  the  pipe,  whilst  the  mandril  M 
makes  the  bore.  It  is  often  thought  by  people  who  have 
had  no  opportunity  of  seeing  pipes  produced,  that  the  lead 
is  forced  from  the  container  whilst  in  a  molten  state ;  this, 
however,  is  not  the  case,  as  the  lead  would  be  simply  squirted 
into  the  air.  Considerable  pressure  is  required  to  form  a 
pipe,  the  intensity  of  the  pressure  varying  with  the  size  of 
pipe  and  the  amount  of  impurity  in  the  lead.  Small  pipes, 
other  things  being  equal,  require  a  greater  hydraulic  pressure 
than  larger  sizes  to  produce.  When  water  pipes  are  made, 
they  are  wound  round  drums  to  form  bundles  as  they  issue  from 
the  machine.  For  making  soil  and  waste  pipes  in  straight 
lengths,  a  cord  is  passed  over  a  pulley  which  is  fixed  high 
over  the  machine ;  one  end  of  the  cord  is  attached  to  the 
pipe,  and  the  other  is  kept  taut  by  a  man  as  the  pipe  is 
being  drawn ;  another  person  measures  the  pipe  and  cuts  it 
off  to  the  required  length. 


8       DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

Lead  pipe  making  machines  differ  considerably  in  structural 
details,  but  their  general  mode  of  operation  is  practically  the 
same  in  each  case.  By  changing  the  die  and  mandril  one 
machine  can  be  used  for  making  the  various  sizes  and  thick- 
nesses of  pipes  in  general  use. 


FIG.  1. — Machine  for  making  lead  pipe. 

Tinned  Lead  Pipe  is  sometimes  confused  with  tin-lined  lead 
pipe,  but  in  the  former  the  surface  of  a  pipe  is  only  covered 
with  a  thin  film  of  tin,  whilst  in  the  latter  the  tin  lining  may 
form  a  substantial  part  of  the  pipe.  The  tinning  process 
is  very  simple,  and  is  effected  as  the  pipe  issues  from  the 
machine.  When  the  inner  surface  of  a  pipe  requires  to  be 


MATERIALS    AND    THEIR    PROPERTIES  9 

tinned,  all  that  is  necessary  is  to  pour  a  little  molten  tin 
inside  the  pipe ;  the  hot  mandril  and  lead  keep  the  tin  in 
the  molten  state,  and  as  the  pipe  is  being  formed  its  inner 
surface  is  covered  with  a  film  of  the  molten  tin. 

When  this  class  of  pipe  was  first  produced  it  was  thought 
that  the  covering  of  tin  would  tend  to  prevent  the  corrosive 
action  which  some  waters  have  upon  lead.  Instead,  however, 
of  the  tinning  preventing  such  action,  it  was  soon  discovered 
that  such  superficial  treatment  often  tended  to  accelerate  it. 
At  their  best,  internally  tinned  lead  pipes  are  little  or  no 
better  than  those  which  are  not  tinned ;  the  tin  alloys  to  a 
more  or  less  extent  with  the  lead,  but  the  interior  surfaces  of 
the  pipes  are  not  evenly  covered.  To  tin  the  outer  surface  of 
a  lead  pipe,  the  die  of  the  machine  is  frequently  formed  with 
a  hollow,  or  pocket,  into  which  molten  tin  is  poured.  Some- 
times the  tin  is  melted  in  the  upper  part  of  the  machine  by 
heating  it  with  gas,  or  by  other  means.  In  the  hollow  of  the 
die  block  the  molten  tin  surrounds  the  pipe,  and  as  the  latter 
passes  through  it  the  external  surface  of  the  pipe  receives 
its  film  of  tin.  To  remove  any  superfluous  metal,  and  to  give 
the  pipe  a  smooth  appearance,  cotton  waste  or  similar  material 
is  pressed  against  the  pipe  as  it  issues  from  the  machine. 

Lead  gas-pipe  which  has  its  external  surface  tinned  is 
frequently  called  composition  pipe,  but  the  term  "  com- 
position "  is  rather  misleading  in  this  case. 

Tin-Lined  Lead  Pipe  is  also  made  by  the  ordinary  pipe 
press,  Fig.  1  ;  but  in  this  case  a  double  process  of  charging  the 
container  C  is  involved.  Instead  of  the  container  being  fully 
charged  with  lead,  an  annular  space  next  the  mandril  M  is 
left,  and  is  afterwards  filled  with  molten  tin.  Thus  whilst 
in  the  container  the  lead  and  tin  really  take  the  form  of  a 
very  thick,  tin-lined  lead  pipe.  The  tin  is  added  after  the 
lead,  and  when  set  hydraulic  pressure  is  brought  to  bear  upon 
the  under  side  of  the  container,  and  as  the  latter  rises  the  two 
metals  are  forced  together  through  the  die,  and  issue  in  the 
form  of  a  compound  pipe,  with  the  tin  and  lead  in  the  correct 
proportion.  The  thickness  of  the  tin  lining  varies  from  about 
IT*  inch  to  TV  inch,  according  to  the  size  and  quality  of  the  pipe. 

Tin-lined  lead  pipes  have  been  largely  used  to  minimise 


10      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

the  risk  of  lead  poisoning  when  portable  waters  dissolve  the 
latter  metal.  Although  these  pipes  are  superior  to  lead  ones 
for  conveying  waters  which  attack  lead,  still  they  are  far  from 
being  satisfactory,  as  traces  of  the  latter  metal  will  generally 
be  found  in  water  which  has  been  lying  stagnant  in  them  for 
a  short  time.  It  is  quite  possible  for  imperfections  to  occur 
during  the  manufacture  of  tin-lined  lead  pipe,  and  doubtless  a 
certain  amount  of  alloying  takes  place  when  the  molten  tin 
comes  in  contact  with  the  lead  during  the  charging  of  the 
machine.  Another  drawback  generally  arises  through  the  un- 
satisfactory method  of  jointing  these  pipes,  owing  to  the  lead 
being  laid  bare  by  some  parts  of  the  tin  lining  being  destroyed. 
It  is  therefore  obvious  that  the  use  of  tin-lined  lead  pipe  is 
no  guarantee  that  a  soft  and  acid  water  which  passes  through 
it  will  not  contain  traces  of  lead.  On  the  other  hand,  if 
a  water  has  no  effect  upon  lead,  tin-lined  lead  pipes  serve 
no  very  special  purpose  excepting  that  they  are  stronger  than 
lead  pipes. 

Insulated  Tin-Lined  Lead  Pipes. — Some  time  ago  an 
attempt  was  made  to  overcome  the  defects  of  ordinary  tin- 
lined  lead  pipe  by  producing  a  pipe  in  which  the  tin  and  lead 
are  kept  separate  by  an  asbestos  covering.  It  is  not  possible, 
in  this  case,  for  the  tin  and  lead  to  alloy  when  making  the 
pipe,  as  the  tin  and  lead  tubes  are  separately  made.  The  tin 
lining  is  afterwards  covered  with  the  asbestos,  and  the  lead 
pipe  requires  to  be  of  sufficient  size  to  receive  them.  The 
composite  pipe  is  then  formed  by  inserting  the  insulated  lining 
into  the  lead  casing,  and  by  afterwards  passing  the  whole 
through  a  special  machine  the  three  materials  are  compressed 
together.  This  form  of  tin-lined  lead  pipe  overcomes  some 
of  the  failings  of  the  first  form,  but  it  is  not  free  from 
defects,  and  trouble  has  been  caused  by  the  tin  lining  col- 
lapsing and  the  water  passages  becoming  stopped.  A  great 
amount  of  care  is  also  necessary  in  making  the  joints,  in 
order  to  prevent  water  coming  into  contact  with  lead  at  these 
points.  It  also  has  the  drawback  of  a  high  initial  cost,  and, 
like  the  ordinary  form  of  tin-lined  pipe,  is  more  costly  to 
fix  than  lead  pipe,  on  account  of  the  special  fittings  and 
extra  time  involved  in  making  the  joints. 


MATERIALS    AND    THEIR    PROPERTIES  11 

Where  water  is  known  to  act  upon  lead,  it  is  desirable 
not  to  use  lead  pipes  of  any  form  for  distributing  water  which 
.is  intended  for  dietetic  purposes.  The  best  form  of  pipe  at 
present  in  use  for  the  conveyance  of  such  water  is  the  tin- 
lined  iron  pipe  with  right-  and  left-hand  screwed  and  socketed 
joints. 

Lead  Traps  and  Bends. — Lead  traps,  which  are  used  at  the 
present  time,  are  the  seamless,  hydraulically  drawn  productions, 
and  the  cast  types  ;  hand-made  lead  traps  with  soldered  seams 
have  had  their  day.  The  seamless  traps  possess  the  advantages 
of  cheapness  and  smoothness,  whilst  those  which  are  cast 
have  the  merit  of  being  stronger  than  the  former.  Opinions 
still  differ  amongst  many  good  plumbers  with  regard  to  the 
merits  and  demerits  of  the  hand-made  and  machine-made  trap. 
It  is  contended  by  some  that  the  modern  drawn  seamless  trap 
will  not  withstand  the  strain  due  to  changes  of  temperature 
to  the  same  extent  as  the  hand-made  trap  witli  soldered  seams  ; 
that  the  former  has  often  failed  in  a  comparatively  short  time, 
whilst  hand-made  traps  fixed  under  similar  conditions  have 
been  much  more  durable.  This  presents  a  problem  worthy 
of  consideration,  because  if  a  certain  fitting  fails  in  a  com- 
paratively short  time  when  compared  with  a  similar  one 
which  is  only  made  in  a  different  way,  the  cause  of  such 
failure  should  not  be  difficult  to  ascertain.  Very  often  when 
comparisons  are  made  some  of  the  most  important  factors 
are  overlooked,  and  thus  the  conclusion  arrived  at  may  be 
only  partly  true.  It  is  quite  possible,  however,  for  a  hand- 
made trap  to  be  much  more  durable  than  a  drawn  one 
under  certain  conditions,  but  the  writer  sees  no  reason 
why  a  seamless  trap  under  ordinary  circumstances  should 
not  be  just  as  durable  as  a  hand-made  one,  provided  it  is 
properly  fixed,  made  of  good  lead,  and  of  sufficient  strength. 
Thickness  for  thickness,  hand-made  traps  are  stronger  than 
those  which  have  been  drawn,  owing  to  the  soldered  seams, 
which  impart  a  fair  amount  of  rigidity.  Should  a  trap  with 
soldered  seams  be  fixed  in  connection  with  a  length  of  light 
lead  waste  pipe,  and  the  pipe  arranged  that  movement  due  to 
expansion  and  contraction  can  freely  take  place,  the  trap 
under  such  conditions  would  have  a  long  life,  and  especially 


1 2      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

if  the  waste  water  passed  through  it  was  not  of  a  very  high 
temperature.  On  the  other  hand,  if  the  same  trap  had  been 
fixed  to  a  length  of  strong  waste  pipe,  through  which  very 
hot  water  was  discharged,  and  no  provision  were  allowed  for 
the  pipe  to  expand,  the  life  of  the  trap  under  these  circum- 
stances would  be  comparatively  a  short  one.  In  the  latter 
case  the  whole  of  the  strain  which  accompanies  expansion 
would  be  concentrated  upon  the  trap,  and  the  latter  would 
naturally  be  distorted  by  the  gradual  increasing  length  of  pipe. 

If,  now,  we  assume  that  drawn  lead  traps  had  been  used 
for  the  cases  already  described,  the  results  would  be  similar 
in  each.  Of  course  it  is  quite  possible  for  special  cases  to 
occur  where  greater  distortion  can  take  place  with  drawn  lead 
traps  than  with  those  with  soldered  seams,  but  where  a  strong- 
form  of  lead  trap  is  desirable  a  cast  one  could  be  used.  Lead 
is  not,  however,  an  ideal  material  for  traps  which  receive  alter- 
nately hot  and  cold  discharges  of  water  ;  and  where  durability 
is  an  important  factor,  traps  of  hard  metal,  such  as  iron  and 
brass,  should  be  used. 

For  general  work  the  cheapness  of  drawn  lead  traps,  and 
the  many  forms  in  which  they  are  made,  are  important 
advantages.  Their  life  may  also  be  considerably  increased 
if  the  waste  pipes  are  arranged  to  prevent  the  pull  and  thrust 
which  accompany  contraction  and  expansion  being  concen- 
trated upon  the  traps. 

Many  of  the  defective,  old,  seamed  lead  traps,  which  have 
been  taken  out  from  time  to  time,  instead  of  being  damaged 
by  different  rates  of  expansion  and  contraction  between  the 
two  different  materials  of  which  they  were  constructed,  were 
chiefly  the  result  of  corrosion  owing  to  lack  of  ventilation. 

Drawn  lead  traps  should  not  be  thinner  in  substance 
than  6-lb.  sheet  lead,  and  a  greater  thickness  as  a  rule 
does  not  proportionally  increase  the  life  of  traps  which 
receive  alternate  discharges  of  hot  and  of  cold  water.  Much, 
of  course,  depends  whether  the  metal  is  pure  or  not.  For 
example,  it  is  quite  possible  for  a  trap  which  is  equal  to 
8-lb.  sheet  lead  to  be  less  durable  than  one  whose  thickness 
is  only  equal  to  6-lb.  lead,  provided  the  lead  of  the  former 
contained  a  higher  percentage  of  impurity. 


MATERIALS    AND    THEIR    PROPERTIES  13 

The  manufacture  of  drawn  lead  traps  and  bends  is 
similar  to  that  of  ordinary  lead  pipe,  but  the  machines 
differ  in  construction.  In  a  trap  making  machine  the  lead 
container  is  arranged  with  a  piston  at  each  end,  whilst 
the  lead  issues  from  the  centre  of  the  machine.  After  the 
container  is  charged  with  lead,  hydraulic  pressure  is  brought 
to  bear  upon  the  pistons,  and  by  manipulating  the  pressure 
on  each  piston  the  issuing  pipe  can  be  curved  or  bent  in 
the  direction  desired.  When  equal  pressures  are  applied 
to  the  pistons  the  lead  issues  from  the  machine  in  the 
form  of  a  straight  pipe,  and  when  differential  pressure  is 
acting  on  the  pistons  the  pipe  curves  in  the  direction  of 
the  greater  force. 

Sheet  Lead. — This  may  either  be  cast  or  milled,  but 
the  former  is  very  seldom  required  at  the  present  time, 
and  it  is  very  doubtful  if  \  per  cent,  of  the  present  day 
plumbers  will  ever  be  called  upon  to  cast  and  lay  it.  Cast 
sheet  lead  when  required  can  be  made  on  a  suitable  casting 
frame  in  the  workshop,  or  other  suitable  place ;  or  it  may 
be  procured  from  a  lead  merchant. 

Cast  Sheet  Lead. — For  roof  work  cast  sheet  lead  is  con- 
sidered by  some  to  be  superior  to  milled  sheet  lead,  but  on 
the  whole  its  drawbacks  outweigh  any  merits  it  may  possess. 
Cast  lead  can  only  be  made  in  comparatively  small  sheets, 
it  requires  to  be  thicker  than  milled  lead,  it  is  not  as  a 
rule  of  uniform  thickness,  and  sometimes  it  is  porous.  It  is 
also  dearer  than  milled  lead,  and  neither  does  it  permit  of 
the  same  neatness  of  finish  when  it  requires  to  be  worked 
into  various  shapes.  The  chief  advantages  of  cast  lead  are 
its  architectural  appearance,  and  it  will  expand  and  contract 
with  less  risk  of  breaking  than  milled  sheet  lead.  The 
latter  is  owing  to  the  molecules  of  cast  lead  being  in  normal 
positions,  whilst  those  of  milled  lead  are  squeezed  into  un- 
natural places,  and  may  be  more  or  less  in  a  state  of  internal 
stress. 

Milled  Lead  is  made  in  sheets  about  33  feet  long  and 
from  7  ft.  6  in.  to  8  feet  in  width.  Some  few  rolling  mills 
make  sheets  up  to  about  40  feet  in  length  and  "9  feet  in 
width.  Narrower  sheets  than  those  usually  made  can  be 


14     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

obtained  if  desired,  and  special  widths  are  often  an  advan- 
tage as  much  scrap  can  in  many  cases  be  avoided. 

Milled  sheet  lead  is  made  by  first  casting  a  block  of 
lead  approximately  8  feet  square  and  6  inches  in  thickness. 
After  this  has  cooled  sufficiently  it  is  hoisted  on  the  rolling 
machine,  and  passed  forwards  and  backwards  between  two 
heavy  chilled  steel  or  cast-iron  rollers,  which  are  located  in 
the  centre  of  the  frame-work  of  the  machine.  The  rolling 
process  is  continued  until  the  block  of  lead  has  been  reduced 
to  about  three-quarters  of  an  inch  thick.  The  flow  of  the 
metal,  due  to  the  enormous  pressure  which  is  brought  to  bear 
upon  it,  is  practically  all  in  a  longitudinal  direction  ;  as  regards 
the  width,  that  is  not  much  affected,  the  edges  only  taking 
a  ragged  or  irregular  form.  When  the  thickness  of  f  inch 
has  been  reached,  the  lengthened  plate  of  lead  is  cut  cross- 
ways  into  suitable  lengths,  which  vary  with  the  size  of  the 
finished  sheet  and  strength  of  lead  required.  Very  often 
two  sheets  are  rolled  at  one  operation ;  this  is  done  by 
rolling  one  of  the  pieces,  into  which  the  whole  plate  has 
been  divided,  until  its  thickness  is  equal  to  about  that  of 
10 -Ib.  sheet  lead;  at  this  point  the  sheet  is  doubled,  when 
by  further  rolling  the  desired  thickness  is  obtained.  The 
ragged  edges  are  now  straightened  and  the  lead  rolled  up. 
When  lead  thicker  than  6  Ib.  per  sq.  foot  is  required  the 
sheets  are  rolled  separately.  Fig.  2  gives  drawings  of  a 
milling  machine.  It  will  be  observed  that  numerous  wood 
rollers  are  arranged  from  end  to  end  of  the  machine,  and 
these  carry  the  lead,  and  of  course  impart  easy  motion  to 
the  lead  when  being  rolled.  Pressure  is  applied  to  the 
centre  rollers  by  the  aid  of  a  wheel  and  suitable  gearing, 
and  the  top  roller  is  raised  and  lowered  by  the  same 
means. 

The  cutting  roller,  which  is  shown  on  the  right  side  of 
Fig.  2,  is  for  trimming  the  edge  of  a  sheet.  One  is  fixed  on 
each  side  of  the  machine,  and  occasionally  a  guillotine 
arrangement  is  also  provided  for  shearing  the  sheets  cross- 
wise. 

Iron. — The  principal  ores  from  which  iron  is  obtained 
are  Ked  Hematite,  Brown  Hematite,  Magnetic  Iron  Ore, 


16      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

and  Siderite.     The  first  three  occur  as  oxides  of  iron,  whilst 
the  latter  occurs  as  a  carbonate  of  iron. 


Iron  takes  three  principal  forms,  viz. :  Cast  Iron, 
Wrought  Iron,  and  Steel.  The  difference  in  their  physical 
and  chemical  properties  is  due  chiefly  to  the  difference 


MATERIALS    AND   THEIR   PROPERTIES 


17 


18      DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 

in  the  amount  of  carbon  which  enters  into  their  com- 
position. 

Cast  iron  contains  over  1J  per  cent,  of  carbon,  and  a 
large  amount  of  other  impurities.  Wrought  iron  is  the 
purest  form  of  iron,  and  only  contains  about  -J  per  cent., 
and  less,  of  total  impurities ;  the  amount  of  carbon  should 
not  exceed  -J-  per  cent.  Mild  steel  contains  less  than 
J  per  cent,  of  carbon,  whilst  hard  steel  contains  from  J  per 
cent,  to  about  2  per  cent,  of  carbon.  Both  forms  of  steel 
are  nearly  free  from  other  impurities. 

The  principal  impurities  in  iron  are  carbon,  manganese, 
phosphorus,  silicon,  and  sulphur.  Cast  iron  at  the  present 
time  is  very  largely  used  in  the  manufacture  of  sanitary 
fittings,  such  as  baths,  lavatories,  etc. ;  for  drainage  work, 
soil  and  waste  pipes,  and  for  boilers,  pipes,  and  fittings  in 
connection  with  low  pressure  hot-water  and  steam-heating 
work. 

Properties  of  Iron. — Cast  iron  is  hard  and  brittle,  and  varies 
in  colour  when  fractured  from  a  silver  white  to  a  dark  gray. 
On  account  of  its  fusibility  it  can  be  run  into  moulds  so 
as  to  take  various  forms.  The  specific  gravity  of  cast  iron 
varies  from  7  to  7'6,  and  a  cubic  foot  weighs  from  437  to 
474  Ib.  Its  tensile  strength  is  comparatively  low,  whilst  its 
resistance  to  a  crushing  force  is  high ;  on  an  average  the 
tensile  strength  of  cast  iron  is  about  7  tons  per  sq.  inch, 
whilst  the  average  crushing  load  is  about  48  tons  per  sq. 
inch.  Cast  iron  is  less  affected  by  oxidation  than  either 
wrought  iron  or  steel. 

Wrought  iron  is  of  a  bluish -white  or  bluish -gray  colour, 
and  it  is  readily  oxidised  with  moist  air.  It  is  very 
malleable  and  ductile,  and  at  high  temperatures  can  be 
forged,  rolled,  and  hammered  into  various  shapes.  The 
average  specific  gravity  of  wrought  iron  is  7 '7 8,  and  it 
weighs  485  Ib.  per  cubic  foot.  Its  average  tensile  strength 
is  22  tons  per  sq.  inch,  whilst  the  average  crushing  load  is 
only  about  17  tons  per  sq.  inch.  It  requires  a  very  high 
temperature  to  effect  its  fusion  and,  unlike  cast  iron,  cannot 
be  run  into  moulds. 

Steel  may  be  hard  or  soft  according  to  the  amount  of 


MATERIALS    AND    THEIR    PROPERTIES  19 

carbon  it  contains.  Like  wrought  iron,  it  can  be  forged  and 
welded ;  it  is  malleable,  ductile,  and  very  tenacious.  Its 
colour  is  bluish-gray,  and  it  is  readily  oxidised  upon 
exposure  to  moist  air.  Ordinary  steel  can  be  tempered  to 
take  different  degrees  of  hardness  by  cooling  in  liquids  such 
as  oil,  water,  etc.  The  tensile  strength  of  ordinary  steel  is 
about  50  tons  per  sq.  inch,  and  its  crushing  load  is  about 
150  tons  per  sq.  inch.  The  strengths  of  mild  steel  vary 
considerably,  and  whilst  they  are  much  less  than  those  of 
ordinary  steel  they  exceed  those  of  wrought  iron.  The 
tensile  strength  of  mild  steel  varies  from  25  to  35  tons  per 
sq.  inch. 

Malleable  Cast  Iron  is  largely  used  for  fittings  in  connection 
with  wrought  iron  tubes,  for  pipe  hangers,  clips,  and  brackets, 
and  for  many  other  small  fittings.  The  property  of  malleability 
is  imparted  to  cast  iron  by  decarbonising  it.  To  effect  de- 
carbonisation  the  cast  fittings  may  be  embedded  in  hematite  or 
oxide  of  manganese,  and  subjected  to  a  red  heat  for  a  period 
which  varies  from  a  few  days  to  several  weeks,  according  to 
the  size  of  the  casting  that  is  being  treated.  This  annealing 
process  is  also  said  to  increase  the  tensile  strength  of  the  iron 
to  about  1*6  times  that  of  cast  iron. 

Iron  Pipes  are  made  of  either  wrought  or  cast  iron,  accord- 
ing to  the  purposes  they  are  intended  to  serve  and  the 
pressure  they  are  required  to  withstand. 

Wrought-iron  pipes  are  of  two  kinds :  the  first  are  those 
which  have  plain  welded  joints,  and  the  second  are  those 
which  have  lap  welded  joints.  The  former  are  used  for 
general  work,  such  as  for  conveying  water,  gas,  or  steam  ; 
whilst  the  latter  are  for  withstanding  high  pressures,  as  in 
hydraulic  work,  and  for  small  bore  hot-water  heating  ap- 
paratus. 

Cast  -  iron  pipes  may  be  classified  under  three  heads. 
Firstly,  those  which  are  cast  in  a  horizontal  position ; 
secondly,  those  cast  on  an  inclined  plane :  and  thirdly,  those 
which  are  cast  when  vertically  arranged.  Pipes  which  come 
under  the  first  head  are  chiefly  those  of  a  light  character, 
such  as  rain-water  pipes ;  frequently  such  pipes  have  thick 
and  thin  sides,  owing  to  the  cores  being  buoyed  or  bent 


20      DOMESTIC   SANITARY    ENGINEERING    AND   PLUMBING 

upwards  when  the  metal  is  flowing  into  the  moulds.  Under 
the  second  heading  fall  the  heavy  section  cast-iron  soil,  waste, 
and  drain  pipes ;  many  water  pipes  are  also  cast  in  this 
position.  When  pipes  are  cast  on  an  inclined  plane  the 
socket  end  is  at  the  higher  point,  and  the  pipes  produced  in 
this  way  are  superior  to  those  cast  in  a  horizontal  position. 

Water  pipes  which  are  required  to  withstand  high 
pressure  should  be  vertically  cast,  and  the  best  and  most 
reliable  cast  pipes  are  produced  in  this  way.  Vertically  cast 
pipes  should  have  their  socket  ends  downwards,  their  cores 
should  be  well  and  truly  formed,  and  they  should  also  be  cast 
at  least  one  foot  longer  than  their  finished  lengths.  The 
extra  length  is  to  ensure  compactness  of  grain  at  the  spiggot 
end  of  the  pipes,  and  it  should  be  cut  off  afterwards  in  a 
lathe.  The  pipes  should  be  true  in  section,  and  be  free  from 
defects  and  flaws  of  all  descriptions.  It  is  very  important 
that  pipes  for  conveying  drinking  water  be  coated  with 
some  preservative  immediately  after  casting,  and  before 
their  surfaces  are  covered  with  a  thin  film  of  rust.  Pipes 
should  be  tested  before  leaving  the  foundry  to  not  less  than 
twice  the  pressure  to  which  they  will  be  subjected  when  laid 
or  fixed  in  position. 

Coatings  for  Iron  Pipes. — By  arresting  corrosion  the  life 
of  iron  pipes  may  be  prolonged  for  a  more  or  less  considerable 
time.  For  this  purpose  different  substances  are  applied  to 
the  surfaces  of  pipes,  or  their  surfaces  are  treated  in  some 
special  way. 

Protective  materials  take  the  form  of  oil  paints,  enamels, 
bituminous  compositions  and  glazes,  or  the  surfaces  of  the 
pipes  may  be  subjected  to  a  barffing  or  galvanising  process. 

Oil  Paints  are  frequently  used  for  treating  the  surfaces  of 
iron  rain-water  pipes,  gas  pipes,  etc.,  but  painting  only  has 
a  limited  life  and  requires  periodical  renewal.  Corrosion  is 
generally  very  active  on  the  inside  surfaces  of  pipes,  and  the 
repainting  of  these  is  generally  omitted  after  once  they  are 
fixed  in  position.  The  inner  surfaces  of  pipes  can  be  easily 
painted  in  the  workshop  or  other  suitable  place,  but  if  the 
coating  is  to  be  successful  the  surfaces  will  require  to  be 
properly  prepared  and  all  loose  scales  and  sand  removed.  A 


MATERIALS    AND    THEIR    PROPERTIES  21 

• 
wire  brush  or  similar  tool  is  very  suitable  for  cleansing  the 

inner  surfaces  of  pipes. 

A  Bituminous  Composition,  such  as  Dr.  Angus  Smith's,  is 
fairly  durable,  provided  the  pipes  have  been  properly  cleansed 
and  no  rust  is  present  when  the  coating  is  applied.  It  is 
essential,  however,  that  dilute  acids  are  not  brought  in  direct 
contact  with  the  coating,  or  the  latter  will  be  readily  destroyed. 
To  apply  the  composition,  it  is  raised  to  a  temperature  of 
about  350°  F.,  when  the  pipes  are  dipped  into  the  hot 
solution,  and  remain  submerged  until  they  acquire  the  same 
temperature  as  the  solution  itself.  The  pipes  are  afterwards 
withdrawn  and  allowed  to  drain.  Dr.  Smith's  preparation 
consists  of  a  mixture  of  coal-tar  and  pitch,  with  a  small 
added  quantity  of  mineral  oil.  It  is  largely  used  for  coating 
cast-iron  soil  pipes,  waste  pipes,  water  pipes,  and  drains. 

Srtiall  ivrought-iron  pipes  when  laid  in  the  ground  can  be 
protected  by  putting  them  in  small  wooden  channels  and 
surrounding  the  pipes  with  pitch. 

Glazes  are  also  frequently  used  for  coating  the  inner 
surfaces  of  cast-iron  soil  pipes  and  drain  pipes,  and  although 
these  may  ensure  smooth  surfaces  when  the  pipes  are  new,  it 
is  very  doubtful  if  glazing  is  worth  the  price  it  costs.  The 
glazes  which  are  applied  to  iron  pipes  are  easily  destroyed 
by  dilute  acids,  and  the  cutting  of  pipes  also  tends  to  damage 
them. 

Barffing. — This  process  may  consist  of  heating  the  articles 
to  be  treated  to  redness,  and  by  subjecting  them  to  the  action 
of  superheated  steam.  The  steam  is  decomposed,  and  a  thin 
adherent  film  of  magnetic  oxide  of  iron  is  formed  on  the 
surfaces,  and  this,  for  a  time,  prevents  further  oxidation 
taking  place.  Barffing  is  suitable  for  boilers  and  hot-water 
pipes. 

Galvanising  is  largely  resorted  to  for  the  protection  of 
wrought-iron  cisterns,  cylindrical  tanks  and  wrought-iron  pipes. 
It  is  very  effective  in  many  cases,  but  certain  waters  readily 
attack  and  destroy  it.  The  galvanising  of  wrought-iron 
pipes  often  tends  to  make  them  brittle,  and  great  care  is 
necessary  when  bending  the  pipes  cold.  If,  however,  these 
pipes  are  heated  to  redness,  so  that  bends  can  be  the  more 


22      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

• 

readily  made,  the  zinc  coating  is  destroyed,  and  the  pipes 
require  to  be  regalvanised.  Galvanising  is  effected  by  first 
removing  any  scales  or  dirt  from  the  articles  to  be  treated, 
afterwards  they  are  thoroughly  cleaned  by  submerging  in  an 
acid  bath,  and  finally  by  dipping  them  into  a  bath  of  molten 
zinc. 

Copper. — This  metal  occurs  in  the  native  state  in  certain 
places,  but  only  in  few  in  sufficient  quantity  to  work  it. 
The  principal  locality  in  which  native  copper  is  found  is  in 
the  district  south  of  Lake  Superior.  The  ores  of  copper 
are  chiefly  found  in  the  form  of  oxides,  carbonates,  and 
sulphides,  the  latter  being  the  most  important.  Sulphides 
are  Copper  Glance,  Copper  Pyrites,  Erubescite,  and  Fahl 
Ore.  In  this  country  Cornwall  is  the  only  county  where 
large  deposits  of  the  ore  are  found. 

Properties  of  Copper. — It  is  a  tough,  very  malleable,  and 
ductile  metal,  and  its  specific  gravity  varies  from  8*6  to 
8 '9,  its  highest  value  being  when  in  the  form  of  wire.  The 
weight  of  copper  per  cubic  foot  varies  from  537  to  555  Ib. 
It  is  one  of  the  best  conductors  of  heat  and  electricity.  The 
tensile  strength  of  cast  copper  is  about  8  J  tons  per  sq. 
inch,  and  when  in  the  form  of  wire  2  6  tons  per  sq.  inch ; 
in  the  sheet  form  its  tensile  strength  is  approximately  14 
tons  per  sq.  inch.  It  can  be  forged  when  either  hot  or 
cold,  and  is  softened  when  heated  to  redness  and  suddenly 
submerged  in  cold  water.  Copper  often  contains  impurities 
such  as  traces  of  lead,  iron,  zinc,  tin,  and  of  other  metals. 

When  in  the  presence  of  moisture  copper  is  covered 
with  a  film  of  basic  carbonate,  and  when  heated  to  redness 
it  is  covered  with  a  film  of  oxide.  It  is  dissolved  by  cold 
nitric  acid,  but  in  the  absence  of  air  it  is  not  affected  by 
either  sulphuric  or  hydrochloric  acid.  In  the  presence  of 
air,  however,  copper  is  attacked  by  weak  solutions  of  these 
acids. 

Coatings  for  Copper. — To  prevent  the  film  of  basic 
carbonate  forming  on  copper-lined  sinks  and  cisterns, 
and  on  pipes,  etc.,  their  surfaces  are  frequently  tinned. 
Copper  pipes  are  also  electro-plated  or  lacquered.  As  the 
salts  of  copper  are  poisonous,  plain  copper  pipes  and 


MATERIALS    AND   THEIR    PROPERTIES  23 

cisterns  are  not  suitable  for  conveying  and  storing  water 
which  is  required  for  human  consumption. 

Sheet  Copper. — Unless  specially  ordered,  sheet  copper  is 
not  usually  made  in  pieces  containing  a  greater  area  than 
1 4  sq.  feet ;  it  is  rolled  to  various  thicknesses  to  suit 
the  many  purposes  for  which  it  is  required.  Common 
sizes  of  sheets  are,  5  ft.  3  in.  by  2  ft.  8  in,,  4  ft.  by  3  ft. 
6  in.,  and  4  ft.  by  2  ft. 

Copper  Tubes  are  of  two  kinds :  (a)  those  which  are 
formed  and  joined  with  longitudinal  seams,  and  (b)  solid 
drawn  or  seamless  tubes.  In  the  first  case  the  edges  which 
are  to  be  joined  are  reduced  in  substance  so  that  they  can 
be  overlapped  a  little,  and  afterwards  they  are  brought 
together  and  brazed.  In  seamless  copper  tubes  the  drawing 
process  tends  to  make  them  brittle,  and  in  order  to  restore 
ductility  it  is  necessary  for  the  tubes  to  be  annealed. 
Copper  tubes  have  a  very  large  sphere  of  usefulness  in 
connection  with  hot  water  supplies,  and  also  in  connection 
with  hot  water  and  steam  heating  work. 

Tin. — There  is  only  one  tin  ore,  and  this  is  known  as 
Cassiterite  or  Tinstone.  It  occurs  in  the  form  of  an  oxide, 
the  chief  deposits  in  this  country  being  confined  to  Corn- 
wall. 

Properties. — Tin  has  a  bright  lustre,  is  very  malleable, 
and  melts  at  about  442°  F.  It  is  not  very  ductile,  and 
the  tensile  strength  of  cast  tin  is  only  about  2  tons  per  sq. 
inch.  Its  specific  gravity  is  7 '2  9,  and  a  cubic  foot  weights 
approximately  455  Ib.  Like  lead,  tin  is  not  a  perfectly 
elastic  metal.  When  bent,  tin  makes  a  crackling  noise, 
and  by  this  means  it  is  easily  distinguished  from  a  tin  and 
lead  alloy.  It  is  not  readily  affected  by  atmospheric  air  at 
ordinary  temperatures,  but  it  is  easily  converted  into  an 
oxide  when  heated  to  redness.  Tin  is  not  affected  by  soft 
acid  waters.  Strong  hydrochloric  acid  and  hot  dilute 
sulphuric  readily  dissolve  tin,  and  it  is  rapidly  attacked  by 
nitric  acid. 

Sheet  Block  Tin  is  largely  used  for  covering  counter  tops 
in  vaults,  and  for  covering  drainers  to  sinks,  etc.  Tin  is 
specially  suited  for  such  purposes  on  account  of  its  cleanly 


24     DOMESTIC   SANITARY    ENGINEERING    AND   PLUMBING 

appearance  and  its  softness ;  the  latter  property  prevents 
it  scratching  and  chipping  glass  and  china  ware. 

Block  Tin  Tube. — This  is  made  precisely  in  the  same 
way  as  lead  pipe,  only  that  a  much  stronger  machine  is 
required  on  account  of  tin  being  harder  than  lead. 

Tin  tubes  are  largely  used  for  spirit  and  beer  pipes, 
as  lead  and  tin-lined  lead  pipes  are  not  suited  for  this 
purpose. 

Zinc  does  not  occur  in  the  native  state,  and  the  principal 
zinc  ores  are  found  as  oxides,  as  carbonates,  and  as  sulphides. 
The  last  is  known  by  the  name  of  Blende,  and  is  the  most 
abundant  and  valuable  ore.  In  England  zinc  is  found  in 
Cornwall  and  in  Derbyshire ;  it  is  also  found  at  the  Isle  of 
Man. 

Properties  of  Zinc. — In  colour  zinc  is  bluish-white,  and 
when  exposed  to  moist  air  it  is  covered  with  a  thin  film 
of  oxide.  Its  specific  gravity  when  cast  is  about  7,  and  a 
cubic  foot  weighs  about  437  Ib.  Zinc  is  a  brittle  metal 
when  cold,  but  it  is  fairly  malleable  when  heated  to  the 
temperature  of  boiling  water.  At  300°  F.  it  can  be 
rolled  into  sheets,  but  when  its  temperature  exceeds  about 
350°  F.  it  again  becomes  brittle.  Its  melting  point  is 
approximately  770°  F.,  and  at  a  red  heat  it  boils.  Zinc 
is  readily  attacked  by  an  acid-laden  atmosphere,  and  dissolves 
readily  in  most  acids.  It  always  contains  more  or  less  im- 
purity, such  as  iron,  lead,  and  other  metals. 

Sheet  Zinc. — The  sizes  of  the  sheets  into  which  zinc 
is  rolled  vary  in  length  from  7  to  10  feet,  but  all  sheets 
have  a  uniform  width  of  3  feet.  The  life  of  zinc  is  com- 
paratively short  in  large  manufacturing  centres,  and  when 
laid  on  roofs  under  otherwise  favourable  circumstances  it  will 
only  last  about  twenty  years.  In  country  districts  it  has  a 
much  longer  life,  provided  it  is  properly  laid  and  the  area 
of  one  piece  is  not  too  large. 

In  the  ingot  form  zinc  is  known  as  spelter. 

Alloys. — An  alloy  may  be  defined  as  a  mixture  of  different 
metals  where  their  union  has  been  effected  by  fusion.  In  an 
alloy  the  metals  are  not  in  proportions  which  produce  a 
definite  chemical  compound,  for  upon  cooling  whilst  in  the 


MATERIALS    AND   THEIR    PROPERTIES  25 

molten  state  it  is  found  that  the  metals  composing  the  alloy 
tend  to  separate  and  arrange  themselves  in  different  layers. 
The  tendency  for  the  constituents  of  an  alloy  to  separate 
themselves  is  very  noticeahle  in  plumbers'  solder,  and  before 
a  plumber  takes  a  ladleful  of  solder  from  the  pot  to  make  a 
joint,  he  first  stirs  it  so  as  to  thoroughly  mix  the  lead  and 
tin. 

An  alloy,  however,  is  not  a  mere  mechanical  mixture, 
which  tends  to  separate  into  its  constituent  parts  under 
favourable  conditions,  and  although  such  separation  takes 
place  to  a  considerable  extent,  it  will  be  found  that  the  layers 
are  not  pure  metal,  but  that  each  has  alloyed  with  it  a  certain 
amount  of  another  nietal. 

Properties. — The  properties  of  alloys  usually  differ  con- 
siderably from  those  of  the  constituent  metals,  alloys  being 
usually  harder  and  more  brittle.  Their  melting  points  are 
frequently  less  than  those  of  their  most  fusible  constituents, 
and  their  tensile  strengths  and  ductility  may  be  either  greater 
or  less  than  those  of  any  constituent  metal. 

The  chief  alloys  (excepting  solders)  with  which  the 
plumber  is  principally  concerned,  are  the  Copper-Tin  alloys, 
and  the  Copper-Zinc  alloys.  From  the  former  are  made  the 
best  qualities  of  water  and  steam  fittings,  whilst  fittings  of  a 
lower  grade  are  produced  from  the  latter  alloys. 

Gun-metal  belongs  to  the  copper-tin  series.  A  strong  alloy, 
and  one  which  will  withstand  the  action  of  acid  waters,  is 
produced  by  a  mixture  of  90  per  cent,  copper  and  ten  per 
cent.  tin. 

An  inferior  gun-meted  to  the  above  is  made  by  combining 
85  per  cent,  copper,  10  per  cent,  tin,  and  5  per  cent, 
lead. 

For  spindles  in  connection  with  valves,  a  harder  gun- 
metal  can  be  produced  by  alloying  with  the  copper  and  tin 
a  small  amount  of  phosphorus. 

Brass. — This  alloy  is  obtained  by  a  mixture  of  copper  and 
zinc.  Brass  may  be  either  yellow  or  white,  the  colouring 
depending  upon  the  percentage  of  copper  which  enters  into 
its  composition.  When  the  amount  of  copper  is  less  than  45 
per  cent,  the  colour  is  white.  The  proportions  of  copper  and 


26      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

zinc  vary  considerably,  and  the  amount  of  copper  may  be 
anything  from  40  to  80  per  cent. 

Ordinary  yellow  brass  contains  6  7  per  cent,  of  copper  and 
33  per  cent,  of  zinc.  Many  of  the  inferior  brasses  contain 
more  or  less  lead.  Common  brass  is  unsuited  for  water 
fittings  when  the  latter  are  used  for  sea- water  and  soft  acid 
waters. 

The  action  of  sea-water  on  copper-zinc  alloys  can  be 
minimised  to  a  great  extent  by  including  in  the  mixtures 
1  per  cent,  of  tin.  Brass  which  contains  iron  and  lead  is 
subjected  to  more  or  less  rapid  corrosion  when  in  contact 
with  sea-water. 

Compositions  of  a  few  other  alloys  are  as  follows :- — 

Red  Brass. — 90  per  cent,  copper  and  10  per  cent.  zinc. 

Muntz  Metal. — 60  per  cent,  copper  and  40  per  cent.  zinc. 

Aluminium  Bronze. — 90  to  97  J  per  cent,  copper  and 
2J  to  10  per  cent,  aluminium. 

German  Silver. — 50  per  cent,  copper,  25  per  cent,  zinc,  and 
25  per  cent,  nickel. 

Soft  Gun-metal. — 95  per  cent,  copper  and  5  per  cent. 
tin. 

The  greatest  tensile  strength  of  a  copper-tia  alloy  is 
approximately  17  tons  per  sq.  inch,  the  relative  proportions 
of  copper  and  tin  being  roughly  88  per  cent,  of  the  former  to 
1 2  per  cent,  of  the  latter  metal.  A  greater  or  less  percentage 
of  tin  diminishes  the  tensile  strength  of  the  alloy. 

In  the  copper-zinc  alloys  the  tensile  strength  reaches  a 
maximum  of  approximately  141  tons  per  sq.  inch,  when  the 
copper  and  zinc  are  in  the  proportion  of  80  per  cent,  of  the 
former  to  10  per  cent,  of  the  latter;  the  tensile  strength 
diminishes  with  either  a  greater  or  smaller  amount  of  zinc. 

Sanitary  Pottery. — Although  it  is  often  thought  that  the 
materials  for  the  production  of  porcelain  goods  are  found  in 
the  neighbourhood  of  the  potteries,  such  is  not  the  case.  The 
principal  materials  employed  to  make  porcelain  are  calcined 
bone,  china  clay,  blue  or  ball  clay,  flints,  and  partially 
decomposed  granites.  China  clay  and  granites  are  obtained 
from  Cornwall,  ball  clay  from  Dorset  and  Devonshire,  and 
the  flints  are  obtained  from  Newhaven  and  Dieppe.  Each 


MATERIALS    AND    THEIR    PROPERTIES  27 

material  has  its  own  special  property,  such  as  for  imparting 
fineness,  plasticity,  and  strength  to  the  clay,  or  for  controlling 
the  rate  of  contraction  when  firing  the  clay. 

To  produce  porcelain  sanitary  fittings  from  the  crude 
materials  to  the  finished  state  takes  several  weeks,  and  much 
skill  and  care  is  involved  as  they  pass  through  the  different 
stages  of  manufacture.  The  first  stage  towards  the  prepara- 
tion of  the  clay  is  the  separate  treatment  of  each  ingredient, 
which  is  ground  in  water  so  as  to  bring  it  into  a  suitable 
state  for  mixing.  Before  the  flints  can  be  ground  they  are 
first  calcined.  In  the  "  slip  house "  the  ingredients  are 
measured  out  and  mixed  in  the  correct  proportions,  and  any 
shade  or  colour  can  be  obtained  by  introducing  into  the  liquid 
"  slip  "  stains  and  metallic  oxides.  The  "  slip  "  now  requires  to 
be  brought  into  the  plastic  state,  and  this  is  done  by  pump- 
ing it  into  clay  presses,  where  excess  of  water  is  removed. 
After  leaving  the  presses,  the  plastic  clay  is  passed  into  the 
pug  mill,  from  which  it  issues  of  uniform  consistency  and 
ready  for  the  potter  to  mould.  The  clay  is  pressed  into  the 
moulds  so  as  to  form  one  homogeneous  mass.  A  mould  is 
made  up  in  a  number  of  parts,  the  exact  number  depending 
upon  the  kind  and  shape  of  fitting  required,  and  great  care  is 
essential  in  joining  the  separate  parts  so  as  to  avoid  cracks 
appearing  at  the  joints  when  the  goods  are  fired.  Before  the 
goods  are  ready  for  the  oven  they  must  be  thoroughly  dried. 
The  firing  process  is  performed  by  placing  the  goods  in 
"  saggars,"  which  are  fireclay  receptacles  of  different  sizes 
and  shapes  and  of  about  1  inch  in  thickness ;  the  "  saggars  " 
afford  protection  from  the  intense  heat  of  the  fires,  and 
subject  all  parts  of  their  contents  to  a  more  nearly  uniform 
temperature. 

The  first  firing  process  is  carried  out  in  the  "  Bisque " 
ovens  or  kilns,  which  are  of  circular  or  other  construction, 
the  firing  being  done  from  a  number  of  points.  The 
"  saggars  "  containing  the  things  to  be  fired  are  built  up  in 
the  ovens,  and  when  the  latter  are  fully  charged  the 
doorways  are  built  up  and  the  fires  lighted.  By  means  of 
dampers  the  draught  is  regulated  and  a  gentle  heat 
maintained  for  about  the  first  3  0  hours ;  the  temperature 


28      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

being  raised  afterwards  to   about    2000°  F.  for  another   24 
hours  or  so. 

The  goods  when  removed  from  the  bisque  ovens  are  in 
a  partially  baked  and  semi-porous  state,  and  whilst  in  this 
condition  any  minor  defects  can  be  rectified,  the  spoiled  or 
damaged  goods  being  thrown  aside.  If  the  articles  are  to 
receive  any  form  of  decoration  this  is  often  done  at  this 
stage,  but  if  the  goods  only  require  a  plain  finish  they  are 
taken  to  the  dipping  house  to  be  glazed. 

The  dipping  process  may  consist  of  passing  the  things 
through  the  dipping-tub,  in  which  glaze  is  suspended  in  water, 
the  ware  absorbing  a  sufficient  quantity  of  the  glaze  to  form 
a  coating  over  its  surfaces.  Before  the  glaze  can  be  con- 
verted by  firing  into  a  hard  and  practically  impervious 
substance  all  moisture  requires  to  be  expelled  by  gradually 
drying  the  goods. 

To  be  fired,  the  treated  goods  are  placed  in  "  saggars " 
as  before,  and  to  protect  the  glazed  surfaces,  and  to 
prevent  them  adhering  to  the  "  saggars,"  the  goods  are 
supported  on  studs.  The  ovens  in  which  the  glazing  is 
completed  are  known  as  "  Glost "  ovens ,  they  are  similar  to 
the  "  Bisque "  ovens,  excepting  they  are  sometimes  a  little 
smaller  and  are  heated  to  a  higher  temperature.  The  firing 
takes  about  24  hours,  and  the  temperature  is  quickly  raised 
in  order  to  fuse  the  glaze  and  produce  a  smooth  and  even 
surface.  After  the  ovens  have  been  cooling  for  about  two 
days  the  contents  are  withdrawn. 

Fireclay  and  Brown  Earthenware  Goods  are  made  from 
coarser  materials,  such  as  the  fireclays  which  overlie  the 
coal  measures.  Different  qualities  of  clays  are  also  produced 
by  mixing  the  coarser  with  the  finer  qualities  along  with 
other  ingredients. 

Earthenware  Drain  Pipes.  —  There  are  two  principal 
classes  of  drain  pipes,  (a)  fireclay  pipes  and  (b)  stoneware 
pipes.  The  clay  for  the  former  is  the  more  abundant  and 
the  more  widely  distributed,  while  that  for  the  latter  is 
chiefly  confined  to  the  counties  of  Dorset  and  Devon. 
Fireclays  are  rather  coarse  grained,  and  the  pipes  made  from 
these  clays  depend  principally  for  their  water-tightness 


MATERIALS    AND    THEIR    PROPERTIES  29 

upon  the  quality  and  thoroughness  of  the  glazing.  On  the 
other  hand,  the  clays  from  which  stoneware  pipes  are  made 
are  very  closely  grained  and  are  denser  than  fireclays. 
Stoneware  pipes  are  much  superior  to  fireclay  pipes,  and 
the  former  are  especially  suited  for  resisting  the  action  of 
acids. 

In  England  earthenware  pipes  of  12  inches  diameter 
and  less  are  made  usually  in  lengths  not  exceeding  2  feet ; 
larger  sizes  being  generally  3  feet  long.  In  Scotland  3  feet 
lengths  are  general  for  all  sizes  of  earthenware  drain  pipes 
which  exceed  3  inches  diameter. 

The  thickness  of  stoneware  pipes  is  usually  equal  to 
about  jL  their  diameters,  but  fireclay  pipes  to  be  of  equal 
strength  would  require  to  be  a  little  thicker  than  this.  The 
relative  strength  of  fireclay  and  stoneware  is  stated  to  be  in 
the  ratio  of  1 0  to  1 2. 

Earthenware  pipes  are  generally  salt  glazed. 

Concrete  Tubes  for  drainage  work  are  now  being  made, 
and  these  are  quite  smooth,  true  in  section,  perfectly  straight, 
and  practically  non -absorbent.  They  are  made  in  steel 
moulds,  and  the  concrete  tubes  may  be  reinforced  with 
metal  rods  when  extra  strength  is  desired.  In  price 
concrete  tubes  compare  favourably  with  earthenware  pipes, 
and  for  large  sizes  of  pipes  concrete  has  the  advantage. 


CHAPTEE    II 
ROOF   WORK 

Metal  Coverings. — The  principal  sheet  metals  which  are 
used  for  roof  work  are  lead,  copper,  and  zinc.  For  general 
work  sheet  lead  possesses  important  advantages,  so  that  its 
displacement  by  other  materials  is  confined  chiefly  to  special 
cases. 

Lead  has  the  advantage  of  adaptability  in  a  marked 
degree,  as  it  can  be  readily  worked  into  shapes  to  fit  almost 
any  position ;  it  is  also  a  very  durable  material,  and  its  cost 
is  not  excessive.  The  principal  drawback  of  lead  is  its 
weight. 

Copper  possesses  the  advantage  of  lightness  when  compared 
with  lead,  and  it  can  be  rolled  and  used  in  much  thinner 
sheets.  Copper  is  a  very  durable  metal,  and  is  specially 
suited  for  covering  domes,  turrets,  and  similar  structures. 

Zinc  may  be  used  in  rural  districts  with  good  results, 
provided  it  is  properly  fixed,  and  removed  from  situations 
where  large  volumes  of  sulphurous  acid  gas  are  emitted.  For 
towns  and  manufacturing  districts  zinc  is  unsuitable  on 
account  of  the  amount  of  sulphurous  and  other  acids  which 
are  always  present  in  the  atmosphere  of  such  localities.  The 
advantages  possessed  by  zinc  are  lightness  and  cheapness. 

When  executing  sheet  leadwork  the  points  which 
require  consideration  are  as  follows : — 1.  That  the  area 
of  one  piece  of  lead  be  not  larger  than  where  movement 
due  to  changes  of  temperature  can  readily  take  place. 
2.  That  the  lead  be  fixed  in  such  a  manner  as  will  prevent 
its  sliding  or  tearing  from  its  original  situation  by  its  own 
weight,  or  being  removed  by  the  force  of  the  wind.  3.  That 
water  be  prevented  from  gaining  access  to  the  woodwork 

30 


ROOF   WORK  31 

supporting  the  lead  by  the  former  rising  between  the  laps  or 
passings.  4.  That  all  woodwork  supporting  lead  be  properly 
laid  to  the  required  falls,  and  that  before  the  leadwork  is 
placed  in  position  all  projecting  nails  be  punched  and  the 
woodwork  swept  clear  of  dirt. 

Narrow  boards  should  be  used  for  gutters,  lead  flats,  etc., 
and  these  should  be  laid  in  the  direction  the  water  will  flow. 

Turning  back  to  the  first  point,  lead,  if  laid  in  very 
large  pieces,  is  unable  to  move  freely  on  account  of  its 
weight  and  its  softness.  Thus,  when  a  piece  of  lead  expands 
or  contracts,  unless  it  can  bodily  move,  stresses  are  concen- 
trated at  one  or  more  points ;  the  result  is  the  lead  begins  to 
buckle,  and  is  eventually  cracked  or  torn.  With  regard  to 
the  maximum  area  of  one  piece  of  lead,  this  should  not,  as  a 
rule,  exceed  20  superficial  feet.  Discretion  of  course  requires 
to  be  exercised,  according  to  the  purpose  for  which  the  lead 
is  required  and  the  position  in  which  it  is  to  be  fixed.  It  is 
obvious  that  when  lead-work  is  laid  in  exposed  situations  it 
should  be  in  smaller  pieces  than  when  in  sheltered  places. 

The  second  point  refers  to  the  methods  of  securing  lead- 
work  in  position,  but  these  will  be  dealt  with  as  the  various 
parts  of  roof  work  receive  consideration. 

With  regard  to  the  third  point,  water  may  gain  access  to, 
and  bring  about  the  decay  of  the  timbers  in  the  following 
ways : — 

(a)  By  capillary  attraction  due  to  accumulation  of  dirt  at 
gutter  drips,  or  by  drips  being  too  small,  (b)  By  driving 
wind  and  rain,  the  latter  getting  under  the  lead  when  the 
drips  are  shallow,  or  owing  to  the  passings  of  joints  having 
insufficient  lap.  (c)  By  defective  workmanship. 

LEAD  FLATS. 

Lead  Flats  usually  include  all  lead  covered  surfaces  which 
can  be  walked  upon.  On  flats  the  leadwork  is  arranged  in 
the  form  of  bays  by  either  introducing  solid  or  hollow  rolls. 
Solid  roll  work  possesses  the  advantage  of  not  being  so  readily 
disfigured  when  walked  upon  as  hollow  roll  work,  and  the 
former  can  be  more  speedily  executed  than  the  latter.  The 


32      DOMESTIC   SANITARY   ENGINEERING    AND    PLUMBING 

chief  drawback  of  solid  roll  work  is  the  difficulty  of  securing 
the  lead  on  inclined  surfaces  so  as  to  prevent  its  sliding  or 
crawling  down,  unless  soldered  dots  are  resorted  to.  As 
ordinarily  carried  out,  solid  roll  work  only  permits  of  the  lead 
bays  being  secured  across  their  top  edges  and  along  their 
undercloaks. 

Hollow  rolls  permit  of  the  lead  being  fastened  by  means  of 
copper  ties  on  both  sides  of  a  bay,  and  thus  very  substantial 
fixings  are  obtained.  In  exposed  situations  the  leadwork  is 
also  less  liable  to  be  displaced  by  high  winds,  as  no  free  edges 
are  left  (except  under  special  circumstances)  at  the  sides  of 
the  rolls.  Wood  cores  are  also  dispensed  with. 

The  chief  drawback  of  hollow  rolls  is  their  liability  to 
disfiguration  by  being  crushed  when  walked  upon,  and  by 
materials  falling  upon  them  during  the  erection  of  buildings. 
In  England  solid  roll  work  is  generally  adopted,  whilst  in 
Scotland  hollow  roll  work  is  predominant. 

Fig.  3  shows  a  portion  of  a  lead  flat  which  is  17  feet 
in  width ;  the  flat  on  three  sides  is  supposed  to  be  bounded 
with  high  walls,  whilst  a  low  parapet  wall  is  represented  in 
front.  As  the  water  must  drain  in  the  case  shown  towards 
the  front  wall,  where  a  gutter  is  formed,  a  drip  will  be 
necessary  to  divide  the  flat  in  order  to  reduce  the  bays  to  a 
suitable  length.  The  left  side  S,  Fig.  3,  shows  how  solid 
rolls  are  arranged,  whilst  the  right  side  H  indicates  how 
hollow  rolls  are  generally  arranged  where  the  drip  or  step 
dividing  the  flat  is  not  more  than  3  inches  deep.  When 
arranging  the  bays  for  a  flat,  their  widths  should  be  governed 
to  a  great  extent  by  the  widths  of  the  sheets  of  lead,  so  as 
to  avoid  producing  unnecessary  scrap.  As  a  rule  the  width 
of  the  bays  should  not  exceed  2  feet  when  their  length  is 
about  8  feet.  If  the  bays  are  short,  their  width,  of  course, 
can  be  increased,  but  the  width  decided  upon  should  cut  up 
the  sheet  of  lead  to  advantage. 

Approximately  9  inches  of  lead  are  required  for  the 
under  and  overcloaks  of  solid  rolls,  and  about  7  inches  for  hollow 
rolls.  Thus  if  a  sheet  of  lead  has  a  width  of  7  ft.  9  in.,  this 
will  cut  into  three  strips,  each  with  a  width  of  2  ft.  7  in. 
Supposing  hollow  rolls  are  used,  then  2'  7"  —  7"  —  2  ft., 


ROOF   WORK 


33 


which  would  be  a  suitable  ^vidth  for  the  bays  when  of 
moderate  length.  For  solid  rolls  we  have  2'  7"  —  9" 
=  1  ft.  10  in.  as  the  width  suitable  for  the  bays. 

Solid  Rolls. — A  common  method  of  treating  solid  rolls  is 
shown  in  Fig.  4.  The  thick  edge  of  the  undercloak  should 
be  reduced  with  a  shave-hook  or  other  tool,  or  a  crease  will 
be  formed  in  the  overcloak.  The  overcloak  is  shown  finished 


DR.R 


FIG.  3. — Plan  of  lead  flat  showing  arrangement  of  solid  and  hollow  rolls. 


off  with  a  width  of  about  one  inch  on  the  flat ;  the  object  of 
the  lap  is  to  stiffen  the  overcloak  at  the  angle,  and  also  to 
prevent  it  slackening  to  a  great  extent  on  the  roll.  To  hold 
the  lead  in  position  the  rolls  require  to  be  a  good  shape  and 
well  undercut,  as  indicated  in  Fig.  4.  For  general  work  a 
wood  roll  should  not  be  less  than  2  inches  high,  its  widest 
part  not  smaller  than  If  inches,  and  the  bottom  should  not 
exceed  1  inch  in  width. 

Instead  of  the  overcloak  being  treated  as  in  Fig.  4,  some- 
3 


34      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

times  the  lap  on  the  flat  is  omitted,  and  the  edge  of  the 
overcloak  is  finished  off  on  the  side  of  the  roll,  about  one 
quarter  of  an  inch  above  the  flat.  It  is  supposed  in  the 
latter  case  that  moisture  is  prevented  from  gaining  access 
by  capillary  attraction  to  the  timbers  which  support  the 
lead.  The  possibility  of  leakage  by  this  means,  however,  is 
often  overrated,  for  where  rolls  have  a  minimum  height  of 
2  inches  it  is  usually  impossible,  under  ordinary  circum- 
stances, for  capillary  attraction  to  occur.  Finishing  off  the 
overcloak  on  the  side  of  a  roll  possesses  the  disadvantage  of 
allowing  the  lead  to  slacken  on  it,  either  when  the  lead  is 
walked  upon  or  by  the  action  of  the  weather. 


FIG.  4. — Section  of  solid  roll  showing  leadwork. 

It  is  desirable  when  laying  lead  on  flats  that  the  wood 
rolls,  after  being  fitted  by  the  carpenter,  be  finally  secured  in 
position  by  the  plumber  as  the  work  of  lead  laying  proceeds. 

Laying  Lead. — Before  a  piece  of  lead  for  a  flat  is  laid  in 
its  place,  assuming  the  necessary  setting  up  and  bossing  in 
connection  with  it  has  been  done,  the  large  flat  surface 
should  be  raised  by  either  striking  it  with  the  hand  or  with  a 
soft  wood  dresser.  The  lead  is  then  laid  in  position,  and  the 
wood  roll  fixed  against  the  upstand  which  represents  the 
undercloak,  and  the  roll  made  secure  by  nailing  it  down.  The 
undercloak  lead  is  easily  pressed  over  the  roll  with  the  hand, 
and  finished  off  with  a  soft  wood  dresser.  For  setting  in  the 
lead  at  the  sides  of  the  rolls,  a  proper  setting-in  dresser 


ROOF   WORK  35 

should  be  used,  or  an  ordinary  beech  dresser  which  has  been 
cut  to  suit  the  shape  of  the  rolls  may  be  used  instead. 

To  get  the  overcloak  tight  on  the  roll  often  presents  a 
little  difficulty  to  the  young  plumber,  but  this  can  be  accom- 
plished by  carefully  bending  the  upstand  well  over  the  roll 
for  the  whole  of  its  length ;  the  lead  can  then  be  made  to 
take  the  shape  of  the  roll  by  partially  setting  it  in  along  the 
free  edge  with  a  large  hammer  and  with  a  spare  piece  of 
wood  roll,  which  has  had  any  sharp  edges  rounded  off.  The 
overcloak  can  afterwards  be  drawn  tightly  over  the  roll,  by 
setting  in  the  sides  with  a  blunt-edged  dresser,  and  finishing 
off  with  an  ordinary  setting-in  dresser  or  other  suitable  tool. 

To  keep  lead  free  from  tool  marks  the  flat  dresser  should 
be  used  as  sparingly  as  possible,  and  if  the  rolls  are  treated  in 
the  manner  described  they  will  present  a  smart  and  clean 
appearance.  Large  flat  surfaces  can  be  left  free  from  marks 
by  using  a  planisher,  which  is  made  from  a  piece  of  scrap 
lead,  in  lieu  of  using  a  dresser. 

Fig.  5  shows  how  finished  solid  roll  work  on  a  flat 
appears  where  a  step  is  necessary  to  reduce  the  length  of 
the  bays.  Overcloaks  should  be  arranged  that  their  free 
edges  are  on  the  side  most  sheltered  from  driving  rain.  The 
step  in  a  flat  must  be  higher,  of  course,  than  the  rolls,  in 
order  to  prevent  water  following  under  the  laps  along  the  rolls 
where  the  latter  butt  against  the  step. 

If,  however,  it  is  found  in  a  flat  that  the  height  of  a 
step  and  the  rolls  are  about  the  same,  and  that  no  great 
departure  from  this  can  be  made,  the  ends  of  the  rolls  in  the 
immediate  neighbourhood  of  the  step  should  have  their  height 
reduced  so  as  to  come  half  an  inch  or  so  below  it. 

Roll  Ends. — The  ends  of  solid  rolls  should  terminate  flush 
with  the  lower  edges  of  flats,  and  not  be  cut  a  little  short  as 
is  often  done.  With  regard  to  the  shape  of  the  ends,  it  is 
unimportant  whether  they  are  cut  off  square  or  cut  sloping. 
Before  working  down  a  roll  end  it  is  essential  that  all  sharp 
edges  are  removed.  Eoll  ends  A,  Fig.  5,  are  not  difficult  to 
work  down,  but  care  requires  to  be  taken  so  that  the  lead  is 
not  unnecessarily  reduced  or  split  at  the  sides  by  too  much 
setting-in.  The  overcloak  B,  Fig  5,  is  more  difficult  to  work 


36      DOMESTIC   SANITARY    ENGINEERING    AND   PLUMBING 

on  account  of  the  lead  requiring  bossing  round  the  lower  roll, 
and  also  finishing  off  with  about  an  inch  lap  on  the  flat 
surface.  In  working  overlap  B,  Fig  5,  the  left  side  of  the 
roll  is  first  dealt  with,  and  that  part  should  be  well  held  down 
to  prevent  it  rising  whilst  the  right  side  is  being  bossed  into 
shape.  The  upper  end  of  roll,  as  at  C,  Fig.  5,  can  readily  be 
dealt  with  by  first  pressing  down  part  of  the  upstand  along 


FIG.  5. — General  view  of  solid  roll  work. 


the  top  of  the  bay,  so  as  to  enable  the  overcloak  at  C  to  be 
bent  round  the  roll.  By  careful  working,  the  lead  is  driven 
into  the  corner  so  as  to  take  the  form  required. 

For  securing  the  bays  the  undercloaks  are  copper  nailed 
to  the  wood  rolls,  but  this  fastening  is  inadequate  to  prevent 
the  bays  creeping  down  unless  the  surfaces  have  little  or  no 
pitch. 

Soldered  Dots. — When  lead  is  laid  on  a  surface  with  a 
moderate  pitch,  and  where  solid  rolls  are  used,  soldered  dots 


ROOF   WORK 


37 


are  frequently  adopted  as  fixings.  For  a  flat  with  a  moderate 
pitch  usually  two  dots  are  made  on  each  bay,  these  being 
located  near  the  lower  edge.  Soldered  dots  may  either  be 
flush  wiped  or  raised,  both  forms  being  shown  in  Fig.  6. 
The  raised  form  is  represented  by  A,  and  the  flush  one  by  B ; 


FIG.  6. — Raised  and  flush  soldered  dots  on  flats. 


but  in  each  case  the  lead  is  held  secure  by  means  of  strong 
screws,  which  are  driven  through  it  into  the  woodwork  be- 
neath. To  make  the  solder  adhere  to  the  screws  they  are 
first  tinned.  When  making  soldered  dots,  the  heads  of  the 
screws  should  be  left  raised  a  little  above  the  lead  that  the 


FIG.  7. — Hollow  roll  with  copper  tie. 

solder  will  flow  beneath,  and  the  whole  be  properly  sweated 
together.  Occasionally  tinned  washers  are  used  to  present  a 
large  surface  to  which  the  solder  will  adhere,  but  if  strong 
screws  are  used  and  their  heads  completely  tinned,  then 
washers  may  be  discarded.  The  solder  over  the  screws  need 
not  be  more  than  about  2^  inches  diameter. 

The  principal  drawback  of  soldered  dots  is  that  they  hold 


38      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


the  lead  too  rigid,  and  after  a  time  it  is  found  that,  where 
they  support  heavy  pieces  of  lead,  the  screws  work  their  way 
up  and  through  the  solder,  owing  to  the  thrust  and  pull  which 
are  concentrated  upon  them.  Of  course  where  dots  are  well 
made,  suitably  placed,  and  the  pieces  of  lead  not  unduly 
large,  it  may  take  many  years  before  the  screws  work  out 
above  the  surface  of  the  solder. 


) 

I      1     ) 

) 

1              1    / 

¥7                 1 

FIG.  8. — View  of  hollow  roll  work  for  lead  flats. 

Hollow  Rolls  are  much  superior  to  solid  rolls  for  sloping 
surfaces,  as  these  permit  of  the  leadwork  being  made  secure 
without  resorting  to  soldered  dots.  These  rolls  are  not  made 
so  large  as  solid  ones,  their  height  as  a  rule  not  exceeding  1 J 
inches;  the  thickness  of  the  lead  affects  the  size  of  hollow 
rolls  to  a  certain  extent. 

In  Fig.  7  is  shown  a  section  of  a  hollow  roll  with  copper 
tie ;  the  latter  is  screwed  to  the  woodwork,  and  the  free  end 
is  turned  between  the  under  and  overcloaks  as  shown. 
Copper  ties  are  fixed  about  2  feet  apart,  and  are  from 


ROOF   WORK 


2  to  3  inches  in  width.  On  account  of  the  under  and 
overcloaks  being  wholly  in  contact  with  each  other  one  bay 
cannot  slip  from  another.  The  leadwork  as  a  whole  is 
prevented  from  bodily  giving  way  by  the  copper  ties,  which 
are  provided  at  regular  intervals  throughout  the  whole  length 
of  the  rolls. 

A  plan  of  hollow 
roll  work  has  already 
been  shown  in  Fig.  3, 
whilst  Fig.  8  gives 
a  part  view  showing 
how  the  rolls  may  be 
treated  where  a  drip 
or  step  occurs  in  a 
flat. 

Where  the  curb 
C,  as  in  Fig.  8,  is  a 
plain  one,  the  roll 
ends  K  are  usually 
finished  off  by  turn- 
ing them  down  on  the 
curb  as  shown.  If  a 
curb  is  in  an  exposed 
situation  it  is  neces- 
sary to  add  a  nosing 
piece,  over  which  the 
lead  is  turned,  as  at 
A,  Fig.  9.  Occasion- 
ally roll  ends  are 
treated  as  at  B,  Fig. 
9,  but  in  the  latter 
case  much  more 
labour  is  involved  in 

turning  the  roll  on  the  curb  or  vertical  surface.  As  a  rule 
the  method  denoted  by  B,  Fig  9,  of  forming  the  end  of  a  roll 
is  unnecessary,  and  not  worth  the  extra  labour  it  entails. 

When  a  step  or  drip  occurs,  as  at  S,  Fig.  8,  it  is  treated 
differently  to  that  where  solid  rolls  are  used.  In  hollow 
roll  work  the  under  and  overcloaks  of  steps  are  "  clinked  "  or 


FIG.  9. — Methods  of  finishing  the  ends  of 
hollow  rolls. 


40      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


•'  welted  "  together,  as  at  C,  Fig.  10.  In  order  to  double  the  lead 
under  where  the  roll  end  of  the  upper  bay  occurs,  the  turned 
end  S,  Fig.  8,  is  cut  to  its  finished  length  ;  the  lead  forming  the 
overlap  is  then  free  at  the  end  of  the  roll,  and  will  admit  of 
being  doubled  under  and  into  position  as  partly  shown  by 
D,  Fig.  10. 

The  upper  end  of  the  hollow  roll  E,  Fig.  8,  or  one  in  a 
similar  situation,  can  be  treated  in  different  ways,  but  the 
method  shown  is  the  simplest  and  has  the  best  appearance. 
Another  method  of  treating  the  upper  end  is  to  turn  the  roll 

practically  its  full 
size  on,  and  to  the 
top  of  the  upstand. 
A  third  method  is 
to  form  a  clink  or 
welt  on  the  upstand 
part. 

The  enlarged 
detail  A,  Fig.  11, 
shows  how  the 
undercloak  at  the 
upper  end  of  a 
hollow  may  be  pre- 
pared, whilst  B  of 
the  same  Fig.  de- 
notes the  overcloak 
in  a  finished  state. 

It  is  essential  when  the  ends  are  treated  as  in  Fig.  1 1  that 
the  lead  of  the  overcloak  is  worked  well  down  and  into  the 
corner  p ;  unless  this  is  done  a  leakage  may  occur  at  that 
point  with  a  heavy  shower  of  driving  rain.  The  undercloak 
A,  Fig.  11,  is  prepared  by  first  bossing  up  the  corner  about 
1 J  inches  high  in  the  ordinary  way,  and  then  by  forming  the 
lead  so  as  to  enable  the  undercloak  to  be  turned  over 
inwards  as  shown.  As  regards  the  overcloak,  that  is  worked 
into  position  in  a  similar  manner  to  that  in  which  solid 
rolls  are  used,  excepting  that  from  pointy,  Fig.  11,  the  free 
end  of  the  overcloak  is  doubled  under  to  form  part  of  the 
roll.  From  the  particulars  supplied  it  will  be  obvious  why 


FIG.  10. 


ROOF   WORK 


41 


hollow  and  solid  rolls  differ- in  arrangement,  see  Figs.  5  and 
8,  when  the  treatment  of  their  ends  is  considered. 

Intersecting  Rolls. — A  part  plan  showing  how  the  lead- 
work  is  arranged  where  solid  intersecting  rolls  are  used  is 
given  in  Fig.  12.  The  numbers  on  the  bays  indicate  the 
order  in  which  they  may  be  laid.  Where  the  intersections 
occur  some  of  the  underlaps  will  require  to  be  cut  out  so 
as  to  avoid  giving  the  rolls  a  clumsy  or  bulged  appearance 
at  those  points.  The  method  of  trimming  the  undercloaks 
is  shown  by  bay  No.  1 2  ;  at  the  top  of  the  centre  roll  part 
of  the  undercloak  is  represented  cut  away,  and  the  free  edge 
should  be  well  reduced  by  a  rasp.  Bay  No.  1,  Fig.  12,  it 
will  be  observed,  has  an  overcloak  on  each  side ;  this  is  owing 


FIG.  11. — Formation  of  the  upper  ends  of  hollow  rolls. 

to  the  overcloaks  of  the  side  bays  being  turned  in  the  same 
direction. 

The  allowance  of  lead  to  cover  the  intersections  requires 
to  be  liberal,  otherwise  there  is  difficulty  in  obtaining 
adequate  laps  and  preventing  the  lead  from  being  torn. 
When  working  an  overcloak  round  the  intersections,  after 
any  particular  part  is  once  in  position  it  should  be  firmly 
held  there,  to  prevent  it  being  withdrawn  when  bossing  at 
another  point.  After  the  rolls  are  covered  the  overeloaks 
should  be  made  secure  by  copper  ties  which  have  been 
previously  introduced.  For  exposed  situations  the  ties 
should  be  about  2J  inches  wide,  and  fixed  at  intervals  not 
exceeding  2  feet  apart. 

In  hollow  roll  work  different  methods  are  adopted  for 


42     DOMESTIC   SANITARY   ENGINEERING   AND   PLUMBING 

dealing  with  intersections,  some  involving  much  more  labour 
than  others  to  carry  out.  For  large  flats,  wood  cores  are 
generally  used  for  the  centre  and  diagonal  rolls,  as  at  D,  Fig. 
13.  Wood  rolls  in  these  positions  simplify  the  work  and 
allow  the  lead  to  be  more  quickly  laid.  No  wood  cores 
are  used  for  small  flats  with  intersecting  rolls,  as  no  special 
difficulties  are  presented  as  in  larger  flats  which  require 
numerous  rolls. 


FIG.  12.— Plan  showing  intersecting  solid  roll  work. 

In  Fig.  13  two  methods  are  shown  of  dealing  with  the 
intersections  of  the  rolls ;  in  each  case  wood  cores  are  used 
for  the  centre  and  diagonal  rolls,  and  the  upstand  of  oppo- 
site bays  is  turned  on  these  cores,  the  free  edges  of  the  lead 
meeting  at  the  top,  as  on  the  left  diagonal  roll  and  on  the 
centre  roll  Fig.  13.  Separate  capping  pieces  are  required 
for  the  wood  rolls,  and  the  right  diagonal  roll  shows  a 
capping  piece  in  position  with  the  lead  worked  round  the 
intersections  and  secured  in  position  with  copper  ties.  With 


ROOF   WORK 


43 


regard  to  the  hollow  intermediate  rolls,  they  may  be  joined 
with  the  wood  cores  by  treating  their  ends  in  a  similar  way 
to  that  shown  in  Fig.  11  ;  and  the  free  edges  of  the  over- 
cloak  at  the  intersection  may  be  trimmed,  as  in  the  left 
diagonal  roll  Fig.  13. 

The  other  method  of  treating  the  ends  of  hollow 
rolls,  where  the  latter  intersect  with  the  wood  cores,  is 
illustrated  on  plan  by  cf,  Fig.  13.  In  this  case  the  ends 


FIG.  13. — Plan  showing  intersecting  hollow  roll  work. 


of  the  hollow  rolls  are  turned  upwards  against  the  centre 
core,  as  shown  by  the  enlarged  detail  A,  Fig.  1 4.  Separate 
capping  pieces,  as  before,  are  required  for  the  wood  cores, 
but  the  re-turned  ends  of  the  hollow  rolls  present  a  rather 
clumsy  appearance  at  the  intersections.  Fig.  14,  B,  gives  a 
section  showing  how  the  ties  are  fixed  to  hold  the  capping 
pieces  in  position.  For  this  class  of  work  the  ties  should  be 
fixed  about  18  inches  apart. 

In  Fig.  13  the  bays  may  be  laid  in  the  same  order  as  in 


44     DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 

the  previous  figure,  but  the  order  may  be  varied,  as  this 
system  of  laying  lead  allows  plenty  of  scope  so  far  as  the 
laying  of  the  bays  is  concerned. 

It  is  sometimes   thought  that  hollow  roll  work  is  more 
subject    to    leakage  than    where    solid   rolls   are   used ;    this 


Hollow  rolls  turned  against  wood  core. 


B 

Copper  tie  and  capping  flashing. 
FIG.  14. 

depends,  however,  upon  the  manner  in  which  the  work  is 
done.  If  hollow  roll  work  is  indifferently  executed,  leakages 
at  some  of  the  corners  will  most  likely  occur ;  on  the  other 
hand,  if  the  work  is  properly  done,  and  the  rolls  not  unduly 
trampled  upon,  hollow  rolls  provide  one  of  the  strongest  and 
best  means  for  securing  lead  on  large  horizontal  or  moderately 
pitched  surfaces. 


ROOF    WORK 


45 


LEAD  GUTTERS 

Lead-lined  gutters,  owing  to  their  width,  require  little  fall, 
and  an  inclination  of  1  in  108,  or  1  inch  in  9  feet,  is  ample 
provided  suitable  drips  are 
If  practicable  the 
of  gutters  between 


made. 

length 

two  drips  should  not  greatly 

exceed  9  feet,  but  for  exposed 

situations  shorter  lengths  are 

desirable. 

Box  Gutters  which  have 
a  uniform  width  need  not 
be  more  than  1 0  inches  wide 
unless  they  are  formed  be- 
tween two  pitched  roofs.  A 
little  extra  width  under  the 
latter  circumstances  is  ad- 
vantageous, as  there  is  less 
danger  of  damaging  the  eaves 
when  walking  in  the  gutters. 

Tapering  Gutters. — Or- 
dinary parapet  wall  gutters 
which  vary  in  width  do  not 
usually  require  their  narrow 
ends  more  than  9  inches 
wide ;  this  width  may  also 
be  reduced  a  little  for  special 
cases. 

Care  should  be  exercised 
when  setting  out  gutters  so 
as  to  keep  the  area  of  the 
leadwork  within  reasonable 
limits. 

If  a  gutter  which  tapers 
is  long,  and  the  fall  is  all 
in  one  direction,  its  width 
rapidly  increases ;  this  is  es- 
pecially the  case  where  the 


r-z 


46      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


roofs  have  a  small  pitch.  Where  possible,  long,  tapering 
gutters  should  be  arranged  in  short  sections,  by  locating 
drip-boxes  at  suitable  points;  when  this  is  done  the  width 
of  gutters  can  be  kept  within  reasonable  bounds. 

As  a  rule  the  height  of  drips  should  not  be  less  than 
2  inches,  and  in  some  districts  a  minimum  height  of  2  J  inches 
is  adopted.  Of  course  very  deep  drips  add  to  the  width  of 
tapering  gutters. 

Fig.  15  gives  a  plan  of  a  gutter  which  is  located  between 
two  pitched  slated  roofs  ;  its  total  length  betwen  the  two 
walls  is  28  feet,  and  this  allows  it  to  be  divided  into  three 
lengths,  each  9  feet  between  drips,  and  with  a  drip-box 


U- 


-J 


FIG.  16. — Drawing  for  ascertaining  width  of  gutter  bottom  at  any  point. 

1  foot  in  length.     Assuming  that  each  roof  has  a  pitch  of 
45°,  the    narrow  end  of    gutter    8    inches    wide,    the   drips 

2  inches  deep,  and  that  each   9   feet  length  has  a  fall  of  1 
inch,  then  under  these  conditions    the  width   of  the  gutter 
bottom,  Fig.   15,  at  the  wide  end  would  work  out  at   1   ft. 
1 0    inches ;    and   the  widths   of    the  gutter   bottom   at    the 
top  of   the  intermediate    drips    would    be    1   ft.    2    in.    and 

1  ft.  8  in.  respectively. 

Supposing,  now,  that  each  roof  in  Fig.  15  had  had  a 
pitch  of  30°  instead  of  45°,  the  remaining  particulars  as 
before  the  widest  end  of  the  gutter  bottom  would  have  been 

2  ft.  8J  in.,  and  the  widths  at  the  top  of  the  intermediate 
drips  about   1   ft.   6J  in.    and    2  ft.    4|    in.     These    values 


ROOF   WORK  47 

clearly  indicate  the  influence  that  slow  pitched  roofs  have 
on  the  widths  of  tapering  gutters. 

A  common  method  of  ascertaining  the  width  of  any 
part  of  a  gutter  prior  to  its  formation  is  indicated  by  Fig.  16, 
which  shows  the  widths  at  different  points  of  the  gutter 
under  consideration.  In  practice  the  sketches  are  made  to 
a  large  scale,  or,  better  still,  full  sized,  so  that  the  dimensions 
can  be  easily  measured  off  with  an  ordinary  rule. 

When  a  gutter  gets  very  wide,  the  width  of  the  lead  to 
cover  it  can  be  broken  by  introducing  one  or  more  rolls. 

A  section  through  ab,  Fig.  15,  is  given  in  Fig.  17.  The 
distance  the  sheet  lead  should  turn  over  the  fillets  in  order 


FIG.  17. — Cross  section  of  lead  gutter  between  two  pitched  roofs. 


to  avoid  water  following  back  under  the  slates  and  getting 
behind  the  leadwork,  chiefly  depends  upon  the  pitch  of  the 
roof.  For  quick  pitched  roofs  it  is  only  necessary  to  turn 
the  lead  about  1  inch  over  the  fillet,  as  on  the  left  side  of 
Fig.  17.  Slow  pitched  roofs,  on  the  other  hand,  should  have 
the  lead  carried  right  over  the  fillet,  and  about  3  inches  up 
the  roof,  as  shown  on  the  right  side  of  Fig.  15. 

Drips. — There  are  two  principal  types  of  drips,  viz. : 
the  square  drip  and  the  splayed  drip,  and  these  are  shown 
in  Fig.  18.  The  lead  is  a  little  easier  to  work  down 
when  the  drip  is  splayed,  and  naturally  some  plumbers 
prefer  it.  Either  form  of  drip  is  satisfactory  when  deep 
enough,  and  where  the  lead  is  properly  worked  over  it. 


48      DOMESTIC   SANITARY   ENGINEERING   AND    PLUMBING 

The  chief  advantage  of  the  square  drip  is  that  the  lead  is 
more  rigidly  held  in  position  than  in  the  splayed  form,  but 
many  plumbers  make  a  poor  job  of  square  drips  by  getting 
the  overcloaks  raised  above  the  wood  bearing. 

Drips  are  easily  worked  down  if  the  upstand  lead,  or 
that  which  lies  on  the  roof  surface,  is  first  bent  down  and 
inwards ;  this  enables  the  end  of  the  gutter  to  be  bent  down 
to  take  the  form  of  the  drip,  when  the  lead  can  be  readily 
bossed  to  take  its  correct  form. 

Sharp  "  chase "  or  "  set "  wedges  should  not  be  used 
when  forming  drips,  as  these  unnecessarily  reduce  the 
lead  where  strength  is  most  required.  At  A  and  B, 
Fig.  18,  the  overcloaks  of  the  drips  are  shown  finished 
off  on  the  sole  of  the  lower  lengths  of  gutter;  this  form 
of  finish  is  desirable  for  drips  which  do  not  exceed  2  inches 
in  depth,  as  it  strengthens  the  lead  at  the  angle  and 
keeps  it  in  position.  Occasionally  the  overlap  of  drips  is 
cut  off  about  J  inch  above  the  lower  angle,  as  at  C, 
Fig.  18.  The  object  of  treating  the  drips  in  the  latter 
way  is  intended  bo  prevent  water  rising  by  capillary  attraction 
between  their  under  and  overlaps,  and  gaining  access  to  the 
woodwork  beneath.  This  source  of  leakage,  however,  is 
often  greatly  exaggerated  in  gutters,  and  it  is  very  doubtful 
if  the  trimming  of  2  inch  drips,  as  at  C,  Fig.  18,  serves  in 
a  small  degree  the  purpose  it  is  intended.  The  height  to 
which  water  will  rise  by  capillary  attraction  between  two 
surfaces  depends  upon  their  distance  apart.  After  gutters 
have  been  laid  for  a  short  time  the  surfaces  at  the  drips, 
which  were  originally  dressed  close  together,  get  a  little 
apart,  and  the  separation  of  the  surfaces  by  natural  agencies 
prevents  capillary  attraction  from  taking  place  in  drips  of 
moderate  depth.  Even  in  drips  which  have  a  depth  of 
1-J-  inches  and  less,  and  where  the  overlaps  are  cut  clear  of 
their  lower  angles,  the  risk  of  leakage  due  to  driving  rain 
is  often  much  greater  than  that  which  is  likely  to  occur 
from  capillarity.  Capillary  grooves  are  often  shown  and 
suggested  for  small  drips,  but  such  grooves  could  only  be  cut 
in  fairly  deep  drips,  and  in  such  cases  their  adoption  would 
serve  no  useful  purpose.  For  drips  over  2  inches  deep 


ROOF   WORK  49 

they  are  often  formed  as  at  G,  Fig.  18,  where  the  under  lap 
is  carried  to  the  top  of  the  drip  and  not  over  it  as  in  A 


Vertical  drip  with  overcloak  finished  on  sole  of  lower  length. 


Splayed  drip  with  overcloak  finished  on  sole  of  lower  length. 


Vertical  drip  with  overcloak  finished  clear  of  lower  angle. 
FIG.  18. 

and  B  of  the  same  Fig.     Where  deep  drips  are  wide,  and 
there  is  danger   of  the    overlaps   being   displaced,  they   can 
be  treated  in  a  similar  manner  to  that  shown  at  C,  Fig.  10. 
Box  Gutters. — An  ordinary  form  of  box  gutter  is  given 
4 


50      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


ill  Fig.  19,  where  the  bottom  for  the  whole  length  of  the 
gutter  is  of  uniform  width ;  the  method  of  treating  the 
leadwork  requires  no  special  comment,  as  the  work  is 
practically  the  same  as  in  the  gutter  already  described.  The 
upstand  lead  y  against  the  wall  is  generally  about  6  inches, 
but  in  some  cases  it  may  be  an  inch  less  than  that.  The 
depth  x,  Fig.  19,  will  necessarily  vary  at  different  points, 
but  that  can  be  ascertained  by  means  of  a  sketch  which 
allows  for  the  slope  of  the  gutter  and  depth  of  drips.  At 
the  higher  end  of  a  box  gutter  the  depth  x,  Fig.  19,  should 
not  be  less  than  2  inches. 


FIG.  19. — Box  gutter. 

Valley  Gutters. — Fig.  20  shows  a  valley  gutter  or  flank, 
and  the  flat  surfaces  from  the  fillets  to  the  angle  need  not 
exceed  4  inches  in  width  unless  the  roofs  have  a  very 
quick  pitch.  The  width  between  the  edges  of  the  slates 
should  be  ample,  to  enable  a  man  to  get  his  feet  into 
the  gutter  when  climbing  up  it.  Where  the  lengths  over- 
lap each  other  about  4  inches  should  be  allowed  for  the 
joint. 

Drip-boxes  or  Cesspools  should  not,  as  a  rule,  be  less  than 
6  inches  deep,  and  where  practicable  they  should  be  arranged 
with  an  open  end  to  discharge  into  a  hopper  or  rain- 
water head.  When  formed  in  this  way  choked  outlets  are 


ROOF   WORK  51 

avoided,  but  many  cases  occur  where  such  drip-boxes  cannot 
be  used. 

On  all  buildings  where  the  box  .type  of  drip-box  is 
necessary  the  latter  should  be  provided  with  an  overflow  in 
case  the  outlet  pipe  gets  choked.  There  are  two  principal 
ways  of  arranging  the  outlet  pipes  from  drip-boxes,  as  illus- 
trated by  A  and  B,  Fig.  21.  In  either  case  the  outlet  pipe 
requires  soldering  to  the  drip-box,  otherwise  an  overflow  pipe 
would  be  no  safeguard  to  prevent  leakage  should  a  stoppage 
occur  at  any  time  in  the  outlet  pipe. 

If  a  drip-box  is  not  very  deep,  the  overflow  pipe  will 
require  to  be  inserted  in  a  flattened  form  to  enable  the 


FIG.  20.— Valley  gutter,  or  flank. 

whole  orifice  to  be  below  the  gutter  end.  A  simple  form  of 
overflow  is  given  at  B,  Fig.  21,  where  the  end  is  shown 
finished  flush  with  the  wall. 

The  question  is  occasionally  raised  in  connection  with 
drip-boxes,  whether  those  that  have  their  angles  bossed  are 
not  superior  to  those  that  are  made  with  soldered  joints  ? 
From  a  practical  standpoint,  provided  that  each  is  well  made, 
one  is  just  as  good  as  the  other  so  far  as  durability  is  con- 
cerned ;  generally  speaking,  however,  unless  a  plumber  is  a 
very  good  lead-worker  he  makes  a  better  job  by  soldering 
deep  angles  than  by  bossing  them  up.  The  making  of  drip- 
boxes  in  practice  is  chiefly  regulated  by  their  height  and 
shape,  the  method  involving  the  least  labour  being  the  one 


52     DOMESTIC   SANITARY   ENGINEERING   AND   PLUMBING 

usually  adopted.  For  example,  if  a  drip- box  like  Fig.  22 
is  required,  it  is  much  easier  to  cut  it  out  of  a  piece  of  lead 
and  solder  the  corners  than  to  boss  it  up.  The  joints  could 
be  burnt  in  lieu  of  soldering  if  desired. 

The  size  of  drip-boxes  is,  of  course,  regulated  by  circum- 
stances, but  it  is  desirable  that  they  are  not  made  unduly 
large  or  there  may  be  difficulty  in  getting  them  into  position. 

Flashings. — To  render  roofs  water-tight  by  the  side  of 
walls  or  other  structures,  lead  flashings  are  usually  employed. 
These  flashings  take  various  forms,  and  different  styles  of 


FIG.  21. — Outlets  from  drip-boxes. 

work  are  adopted  for  similar  purposes  in  different  parts  of 
the  country.  Plain  flashings  take  the  following  forms : — 
1.  Soakers  and  cap  flashings.  2.  Cover  flashings.  3.  Secret 
gutters.  4.  Exposed  gutter  flashings. 

Soakers  and  cap  flashings  make  undoubtedly  the  best 
work,  so  far  as  weathering  and  durability  are  concerned,  but 
a  large  part  of  the  work  requires  to  be  done  on  the  roof 
after  it  is  slated  or  tiled. 

Cover  flashings  are  not  suitable  for  exposed  situations, 
nor  for  gable  walls  and  similar  structures  which  make  greater 
angles  than  90°  with,  and  above,  the  courses  of  the  slates. 
These  flashings,  however,  are  satisfactory  for  general  work, 


ROOF   WORK 


53 


View  of  drip-box. 


UNDER  LAP 


UNDER  LAP.  ' 


Development  of  lead  for  lining  drip-box  shown  above. 
FIG.  22. 


54     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

provided  the  situations  in  which  they  are  fixed  are  sheltered 
from  high  winds.  Cover  flashings  are  easily  fixed,  but  the 
greater  part  of  the  work  requires  to  be  done  when  the  slates 
are  in  position. 

Secret  gutters  possess  the  advantage  of  allowing  the  lead- 
work  to  be  done  before  the  slating,  but  they  are  liable  to 
give  trouble  by  getting  choked  with  moss,  leaves,  and  other 
debris. 

Exposed  gutter  flashings  are  similar  to  the  last,  but  they 
are  wider,  and  are  not  liable  to  be  choked  like  Secret  gutters. 


FIG.  23. — Soakers  along  with  continuous  step  flashing. 


The  form  of  roof  construction,  it  will  be  found,  regulates  to 
a  great  extent  the  use  of  any  particular  class  of  flashing.  In 
England,  for  example,  it  is  the  general  custom  (excepting  the 
better  class  structures)  to  simply  nail  the  slates  to  battens 
or  laths,  which  are  in  turn  nailed  across  the  rafters  of  a  roof. 
This  kind  of  roof  construction,  unless  specially  prepared, 
does  not  lend  itself  to  either  form  of  gutter  flashing,  but  is 
better  suited  for  cover  flashings  and  soakers,  which  are  largely 
used  throughout  England. 

In  Scotland  roofs  are  generally  boarded,  and  the  slates 
are  nailed  to  the  boards.  Such  roofs  are  therefore  well 
adapted  for  gutter  flashings,  and  this  is  probably  the  chief 


ROOF   WORK  55 

reason  why  the  exposed  form  v  of  gutter  flashing  is  so  largely 
used  in  North  Britain. 

In  roof  work  it  is  a  decided  advantage  to  be  able  to  fix 
nearly  the  whole  of  the  lead  before  a  slate  or  tile  is  in  position. 

A  small  portion  of  a  gable  wall  and  roof,  Fig.  23,  shows 
how  soakers  and  step  flashings  are  commonly  arranged. 
A  soaker  is  provided  for  each  row  of  slates,  and  the  lap  allowed 
is  the  same  as  that  for  the  slates.  As  a  rule  soakers  do 


Fro.  24. — Method  of  setting  out 
continuous  step  flashings. 


not  require  to  exceed  7  inches  in  width,  irrespective  of  the 
size  of  slate  ;  that  allows  an  upstand  of  3  inches  and  4 
inches  under  the  slates.  The  length  of  soakers  can  be  found 
by  adding  the  lap  to  the  full  length  of  slate,  then  dividing 
by  2,  and  by  adding  to  the  result  -J-  an  inch.  Thus  if 
slates  are  used  which  are  20  inches  long,  and  are  laid  with  a 

20  -f-  3r-\ 

—  -)+  2 


inches. 
Step  Flashings  may  be  made  in  single  steps  or  they  may 


56      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

take  the  continuous  form,  the  latter  being  represented  in 
Fig.  23.  When  setting  out  continuous  step  flashings  it  is 
essential  that  the  lead  from  which  they  are  cut  be  wide 
enough  to  allow  the  free  edges  of  the  steps  to  slope  well 
backwards.  If  the  lead  is  narrow,  the  free  edges  of  the  steps 
may  be  nearly  vertical,  and  rain  may  be  driven  in  behind 
the  lead  and  leakage  may  result.  The  lead  to  form 
the  steps  and  to  overlap  the  soakers,  as  in  Fig.  23,  should 
not  be  less  than  6  inches  in  width.  To  mark  where  the 


Fig.  25. — Cover  flashing. 

turnings  for  brick  joints  come,  the  strip  of  lead  should  be 
fixed  temporarily  in  position,  when  a  short  straight  edge  can 
be  laid  along  the  joints  and  marks  continued  from  the  latter 
across  the  lead.  After  the  positions  for  the  turnings  have 
been  obtained,  an  inch  or  thereabout  is  allowed  on  each 
step  for  going  into  the  joint,  and  the  surplus  lead  cut 
out. 

Fig.  24  shows  how  a  length  of  step  flashing  is  prepared, 
and  how  it  appears  prior  to  turning  the  allowance  at  the  top 
of  the  steps.  For  exposed  situations,  the  strength  of  lead  for 
step  flashings  should  ijot  be  Jess  than  5  Ib.  per  square  foot. 


ROOF   WORK 


57 


The  thickness  of  the  lead  for  soakers  should  be  regulated 
by  the  character  of  the  slating,  so  as  not  to  unduly  tilt  the 
slates.  Generally  speaking  the  strength  should  not  exceed 
5  Ib.  per  square  foot. 

Cover  Flashings. — In  Fig.  25  a  piece  of  cover  flashing  is 
given,  and,  as  its  name  implies,  the  lead  is  simply  secured  on 
the  top  of  the  slates,  and  the  whole  width  of  the  flashing  is 
usually  in  one  piece.  The  lead  which  covers  the  slates  is 


FIG.  26.— Secret  flashing. 


usually  about  5  inches  in  width,  and  the  upstand  in  which 
the  steps  are  formed  should  not  be  less  than'  6  inches. 
Cover  flashings  should  be  fixed  in  comparatively  short 
lengths.  To  prevent  water  following  between  the  flashing 
and  the  slates,  and  leaking  into  the  roof,  the  slates  are 
tilted  from  the  wall  by  means  of  a  wood  fillet,  as  in  Fig.  25. 
The  lead  on  the  slates  is  held  in  position  by  copper  or 
lead  ties,  which  are  obliquely  fixed,  and  clipped  round  the 
free  edge  in  the  manner  shown.  The  ties  should  not  be 


OF   THE 

UNIVERSITY 


58     DOMESTIC   SANITARY   ENGINEERING    AND    PLUMBING 


less  than  2  inches  wide,  and  fixed  from  24  to  30  inches 
apart.  Lead  ties  are  not  so  satisfactory  as  copper  ones, 
and  where  the  former  are  used  they  should  be  cut  from  lead 
weighing  not  less  than  6  Ib.  per  square  foot. 

Secret  Gutters. — The  secret  gutter  flashing,  Fig.  26,  has 

a  separate  cap  flashing,  the 
upper  edge  of  the  latter  being 
fixed  in  a  groove  which  is 
cut  in  the  stonework.  Secret 
gutters  are  made  of  slightly 
varying  widths,  but,  as  the 
term  implies,  no  lead  on  the 
roof  is  intended  to  be  in 
view.  Their  general  forma- 
tion is  shown  in  Fig.  26,  and 
the  width  of  lead  on  the  roof 
FIG.  27.— Gutter  flashing.  surface  may  vary  from  1J  to 

about  2£  inches.     The  slates 

cover  the  channel  to  within  half  an  inch  of  the  upstand  lead. 
By  means  of  a  fillet  the  outer  edges  of  the  slates  are  raised 
a  little,  and  this  prevents  the  water  following  round  their 
edges  and  getting  beneath  them. 


FIG.  28.— Gutter  flashing  with  roll. 

Another  means  to  prevent  leakage  when  secret  gutters 
are  used  is  to  double  the  edge  of  the  lead  back  on  the  fillet, 
as  at  A,  Fig.  26.  The  latter  mode  of  treatment,  however, 
seldom  serves  any  useful  purpose,  as  the  slater  usually 
flattens  down  the  free  edge  on  the  fillet  in  order  that  the 
slates  may  rest  firmly  on  the  woodwork.  Secret  gutters,  as 


ROOF   WORK 


59 


previously  stated,  are  readily  choked,  and  for  this  reason  there 
are  many  situations  in  which  they  should  not  be  used. 

Exposed  Gutter  Flashing. — This  is  illustrated  by  Fig.  27, 
and  it  will  be  observed  that  it  resembles  to  a  great  extent 
the  secret  gutter.  In  Fig.  27,  however,  the  space  between  the 
fillet  and  the  wall  is  usually  about  6  inches,  and  in  this  case 
it  is  not  liable  to  stoppage  like  a  secret  gutter  as  it  can  be 
flushed  out  with  a  heavy  shower  of  rain.  When  a  moderate 
volume  of  water  is  delivered  from  a  higher  to  a  lower  roof,  or 


FIG.  29. — Arrangement  of  leadwork  in  connection  with  a  plain  dormer. 

where  a  large  volume  of  water  is  likely  to  flow  down  an 
exposed  gutter,  the  latter  is  usually  modified  to  take  the 
form  given  in  Fig.  28,  where  the  roll  prevents  the  water 
rushing  over  the  fillet  and  under  the  slates. 

Dormers. — A  method  of  rendering  a  dormer  in  a  slated 
roof  water-tight  is  illustrated  in  Fig.  29.  The  apron  which 
lies  on  the  slates  at  the  front  of  the  dormer  is  first  fixed  in 
position,  and  it  should  be  continued  over  the  framework,  with 
the  upper  part  of  the  structure  erected  upon  it.  Unless  the 
apron  flashing  is  treated  in  this  manner  there  is  difficulty  in 
making  a  dormer  weather  properly  along  the  front.  Although 


60      DOMESTIC   SANITARY    ENGINEERING   AND   PLUMBING 

the  exposed  gutter  flashing  is  shown  at  the  sides  of  the 
dormer,  either  soakers  or  cover  flashings  may  be  used  instead. 
The  cheeks  or  sides  are  each  covered  with  two  pieces  of  lead, 
which  are  joined  by  vertical  "  clinked  "  or  "  welted  "  seams. 
Of  course  the  number  of  pieces  to  cover  one  side  would  be 


FIG.  30. — Details  of  leadwork  for  dormers. 

regulated  by  the  size  of  the  dormer.  Where  the  top  is  com- 
paratively small,  as  in  Fig.  29,  only  one  piece  of  lead]  is 
necessary  to  cover  it,  but  when  large  two  or  more  pieces 
may  be  essential.  The  top  edges  at  the  front  and  sides  of 
the  dormer  are  shown  with  a  simple  finish,  but  this  part 
may  be  made  ornamental  by  introducing  mouldings.  In 


ROOF  WORK 


61 


either  case  the  leadwork  requires  to  be  well  secured  along  the 
top  edges  to  prevent  its  being  blown  up  by  high  winds. 

Enlarged  details,  Fig.  30,  show  more  clearly  how  the 
leadwork  in  connection  with  dormers  is  secured.  The  apron, 
or  barge  flashing,  A,  it  will  be  noted,  after  passing  over  the 
top  of  the  framework  is  turned  upwards  inside.  In  lantern 
lights  the  apron  flashings  are  treated  in  the  same  manner, 
but  instead  of  dressing  the  lead  close  to  the  framework  a 
small  cavity  is  sometimes  left  between  the  lead  and  wood- 
work, in  order  to  receive  and  to  discharge  any  water  of 
condensation.  B  shows  how  the  cheeks  and  top  may  be 


FIG.  31. — Box-gutter  between  wall  and  glass  roof. 

treated,  the  lead  being  supported  along  the  bottom  edge 
with  suitable  ties.  At  C  a  vertical  clink  or  welt  is  given  for 
joining  the  pieces  of  lead  which  cover  the  cheeks.  D  shows 
how  the  lead  is  arranged  at  the  top  of  the  dormer;  the 
reason  for  doubling  the  free  edge  of  the  lead  under  along  the 
front  edge  is  for  strengthening  purposes.  The  lead  should 
also  be  supported  and  secured  by  ties  being  inserted  in  the 
"  clinked  "  or  welted  seams. 

The  strength  of  lead  for  covering  dormers  or  similar 
structures  should  be  approximately  as  follows :  Tops  6  or 
7  Ib.  per  square  foot.  Sides  and  aprons,  5  or  6-lb.  lead. 
Exposed  gutter  flashings,  5  or  6-lb.  lead.  Apron  flashings 
should  overlap  the  slates  by  about  5  inches. 


DOMESTIC   SANITARY   ENGINEERING   AND   PLUMBING 


Glass  Roofs  and  Skylights. — When  a  glass  roof  drains 
into  a  box  gutter,  as  in  Fig.  31,  it  will  be  found  easier 
and  quicker  to  lay  the  gutters,  if  separate  flashings  are 
fixed  beneath  the  ends  of  the  glazing  bars.  Where  the 
gutter  and  flashing  are  in  one  width  there  may  be  much 
difficulty  in  getting  them  into  position.  If  separate  flashings 
are  used  the  gutters  can  be  laid  in  the  ordinary  way,  and  it  is 
an  easy  matter  to  slide  the  flashings  under  the  ends  of  the 
glazing  bars,  which  have  been  slotted  to  receive  them. 

The    side    flashings    for   skylights    may   be   arranged   in 
different   ways,  depending  upon  the 
circumstances  of  the  case.    If  soakers 
are  used  for  the  sides  of  a  fast  light, 
which  stands  4  inches  or  so  clear  of 
the  roof,  separate  cap  flashings   are 
generally  used  for  covering  the  top 
edges  of  the    soakers,  and    to    turn 
over    on    the    upper  surface   of  the 
woodwork.     Where  a  skylight  is  only 
raised  a  little 
above  the  roof, 
separate     cap 
flashings  can- 
not   be    used, 
and      under 
these      condi- 
tions   it     is 
customary    to 

make  the  soakers  with  a  higher  upstand,  and  to  dress  the 
latter  over  the  upper  edge  of  the  light.  Gutter  or  cover 
flashings  may  be  used,  of  course,  in  lieu  of  soakers,  but 
the  principle  is  the  same  irrespective  of  the  particular 
kind  of  flashing  which  may  be  adopted. 

Cornices.  —  Both  stone  and  wood  cornices  are  often 
covered  with  lead  in  order  to  preserve  them  from  disinte- 
gration and  decay.  For  covering  cornices  similar  to  Fig.  32 
the  lead  is  usually  cut  in  lengths  equal  to  the  width  of  the 
sheet,  and  the  pieces  are  joined  together  with  clinked  or 
welted  seams. 


FIG,  32. — Lead  covering  for  stone  cornice. 


ROOF   WORK 


63 


On  stone  cornices  the  lead  is  easily  secured  in  position  by 
means  of  lead  dowels,  which  are  introduced  at  intervals 
varying  from  2  to  4  feet  according  to  the  width  of  the 
cornice.  The  dowels  may  be  formed  by  cutting  dovetailed 
holes  in  the  stonework  prior  to  the  fixing  of  the  lead ;  when 
the  latter  is  in  position,  small  holes  are  bored  into  it  im- 
mediately over  those  in  the  stonework,  and  the  lead  shaved 
around  the  holes  and  their  edges  turned  upwards,  as  in 


FIG.  33. — Treatment  of  joint  of  leadwork  in  connection 
with  channel  cornice. 


Fig.  32.  A  brass  or  iron  mould  is  afterwards  placed  over  the 
prepared  holes,  which  are  run  full  of  molten  lead. 

Another  method  of  securing  lead  on  stone  cornices,  is  to 
make  holes  in  the  latter  as  above  described  and  to  run  them 
full  of  lead.  After  the  cornice  is  covered,  tinned-headed 
screws  are  driven  through  the  sheet  lead  into  the  dowels  or 
plugs,  and  soldered  dots  wiped  over  them. 

When  cornices,  such  as  Fig.  32,  are  of  wood,  the  best 
method  of  securing  the  leadwork  is  by  means  of  copper  ties, 
which  are  fixed  in  the  clinked  or  welted  joints. 

It  is  a  good  plan  to  dress  the  lead  square  over  the  edge 


64      DOMESTIC   SANITARY   ENGINEERING   AND   PLUMBING 

of  a  cornice,  and  to  trim  it  off  so  that  it  may  hang  free  of  the 
stone  or  woodwork.  By  doing  this  an  even  edge  is  preserved, 
and  water  is  prevented  from  trickling  down  and  disfiguring 
the  moulding  of  the  cornice. 

For  covering  a  channel  cornice,  Fig.  33,  the  lead  is  laid 
in  as  long  lengths  as  possible,  and  the  joints  either  soldered 
or  made  by  burning  them.  As  these  cornices  are  fixed  level, 


FIG.  34.— Method  of  covering  pitched  stone  copings 
with  lead. 


the  only  fall  available  is  that  obtained  by  cutting  the  channel 
deeper  at  the  outlet  than  at  any  other  part.  The  joints  in 
the  channel  should  be  made  flush  on  account  of  the  small 
amount  of  fall  obtainable.  It  is  not  necessary  to  solder  the 
joint  right  across  on  a  channel  cornice,  but  a  clinked  or 
welted  seam  can  be  made  for  all  except  the  channel. 

Pitched  Stone  Copings. — Sometimes  it  is  essential  to  cover 
pitched  copings  with  lead,  but  the  general  method  of  securing 
the  lead  work  with  dowels  or  dots  is  not  satisfactory  in  this 


ROOF    WORK 


G5 


case.  Dowels  or  dots  form  rigid  fixing,  and  although  they 
answer  for  cornices  more  freedom  is  necessary  for  supporting 
heavy  pieces  of  lead  on  comparatively  quick  pitched  surfaces. 
A  good  plan  of  securing  leadwork  on  pitched  copings  is 
indicated  in  Fig.  34.  The  length  of  each  piece  can  be 
regulated  to  a  great  extent  by  the  pitch  of  the  coping,  but 
in  any  case  the  pieces  should  not  be  very  long.  It  will  be 
observed,  upon  reference  to  Fig.  34,  that  the  top  end  of  each 
piece  of  lead  is  turned  into  a  groove  in  the  stonework,  and  in 
the  same  groove  copper  ties  are  fixed  for  supporting  the  next 
higher  piece.  Thus  each  piece  of  lead  is  well  secured  along 


FIG.  35. — Method  of  securing  lead  on  ridges  with  copper  ties. 

the  top  and  bottom  edges,  and  yet  sufficiently  free  to  allow  a 
little  longitudinal  and  lateral  movement. 

Hips  and  Ridges. — Eolls  for  ridges  and  hips  require  to  be 
raised  above  the  slates  that  the  lead  may  be  able  to  grip  them 
without  pressing  upon  the  edges  of  the  slates.  An  old  but 
very  good  method  of  arranging  these  rolls  is  that  of  fixing 
them  on  spikes,  which  are  driven  into  the  ridge  and  hip 
timbers. 

Another  method  is  shown  in  Fig.  35,  where  the  rafters 
are  arranged  to  come  below  the  top  of  the  ridge  piece,  and 
where  the  edges  are  champered  that  the  top  of   the  ridge 
piece  may  be  no  wider  than  the  bottom  of  the  roll. 
5 


66       DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

For  general  work,  ridge  and  hip  rolls  are  similar  in  size 
to  those  for  flats,  but  larger  ones  are  used  for  special  work. 
The  lead  wings  which  overlap  the  slates  should  not  be  less 
than  5  inches  in  width,  and  where  ornamental  wings  are 
desired  greater  widths  will  be  necessary. 

Fixings  for  Hips  and  Ridges. — The  lead  on  ridge  and  hip 
rolls  requires  to  be  specially  well  secured,  or  it  is  liable  to  be 
dislodged  by  high  winds  or  to  "  creep  "  down  the  hips  by  its 
own  weight.  Copper  or  lead  ties  are  frequently  used,  as  in 
Fig.  35,  so  as  to  grip  the  lead  on  each  wing  and  to  keep  it 


FIG.  36. — Method  of  securing  lead  on  hips  or  peends. 

tight  on  the  roll.  The  ties  are  fixed  prior  to  the  wood  roll, 
and  spaced  about  2  feet  apart. 

On  the  right  hip  in  Fig.  3  6  the  lead  is  fastened  by  copper 
or  galvanised  wrought  iron  bands ;  they  take  the  form  of  the 
roll,  and  turn  under  the  edge  on  each  side  of  the  wings.  The 
bands  are  screwed  or  railed  down  on  the  rolls. 

Secret  fixings,  which  consist  of  small  pieces  of  lead  about 
4  inches  long,  are  sometimes  soldered  on  the  under  side  of  the 
lead  which  covers  the  rolls  ;  these  fixings  are  dressed  round 
the  rolls  and  nailed  down,  whilst  the  lead  for  covering  the 
rolls  remains  boxed  up  in  the  usual  way.  For  good  work, 
secret  fastenings  should  be  sunk  flush  with  the  top  of  the 


ROOF    WORK  G7 

rolls.  They  are  very  serviceable  for  securing  the  lead  on 
quick  pitched  hips  where  a  neat  form  of  fixing  is  required. 

Lead-headed  nails,  along  with  the  use  of  copper  ties,  make 
simple  and  cheap  forms  of  fixings,  and  are  effective  for  holding 
the  lead  in  its  place. 

Bossing  the  lead  round  the  ends  of  rolls  is  a  practice 
occasionally  adopted  when  covering  large  rolls  on  very  quick 
pitched  roofs.  The  rolls  should  be  in  about  5  or  6  feet 
lengths,  and  after  the  bottom  length  is  fixed  it  is  covered 
with  lead ;  the  lead  is  left  longer  than  the  wood  roll,  and  is 
then  bossed  over  its  upper  end  to  afford  a  means  of  support. 
After  the  first  length  is  finished  another  is  placed  in  position, 
and  covered  in  a  similar  manner  to  the  first.  This  pro- 
cedure is  followed  until  the  hip  is  complete. 

The  method  of  securing  lead  on  ridges  and  hips  is  chiefly 
regulated  by  their  situation  and  the  shape  of  the  rolls.  It  is 
clearly  obvious  that  the  same  amount  of  fastening  will  not 
be  necessary  in  sheltered  places  as  in  situations  which  are 
exposed  to  high  winds.  Kolls  when  not  of  a  good  shape  may 
require  additional  fixings  on  that  account. 

Kidge  rolls,  like  Fig.  35,  when  covered  with  5  to  7-lb. 
lead  admit  of  the  latter  being  well  secured  with  ties,  but 
these  fixings  are  liable  to  failure  unless  the  rolls  are  suitably 
shaped  and  the  ties  freely  used. 

Ordinary  ties,  as  in  Fig.  35,  are  insufficient  fixings  for  hip 
rolls,  and  additional  fastenings  should  be  used. 

Galvanised  iron  or  copper  bands  when  fixed  on  rolls  do 
not  present  a  good  appearance,  but  they  have  the  merit  of 
being  easily  fixed  and  are  effective  so  far  as  securing  the  lead 
is  concerned. 

Secret  fixings  are  very  suitable  where  strong,  neat  work  is 
required,  but  their  use  makes  the  lead  more  costly  to  lay  on 
account  of  the  extra  labour  they  involve. 

Where  two  lengths  of  lead  are  joined  on  ridges  they 
should  overlap  each  other  by  about  4  inches ;  on  ridges  the 
overlap  should  not  be  less  than  3  inches. 

Ornamental  Ridging. — On  many  public  and  other  buildings 
ridges  are  frequently  of  an  ornamental  character,  and  some 
particular  design  is  either  cut  or  formed  in  the  wings  of  the 


68       DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

leadwork.  In  these  cases  the  rolls  are  much  larger  than 
those  generally  employed,  so  as  to  give  them  a  prominent 
appearance  when  viewed  from  a  distance.  As  the  lead  for 
ornamental  ridgings  requires  to  be  wide  it  is  often  necessary 
to  fix  it  in  two  or  more  widths,  and  afterwards  to  clink  or 
welt  them  together. 

When  various  designs  require  to  be  bossed  on  the  wings 
of  the  leadwork,  the  wings  should  be  separately  fixed  to 
permit  of  the  work  being  more  readily  accomplished,  as 
suitable  blocks  can  often  be  screwed  down  to  a  bench  and  the 
lead  worked  down  over  them. 

Torus  Rolls. — In  Fig.  37  are  shown  three  methods  of 
arranging  the  flashings  in  connection  with  a  mansard  roof  or 
similar  structure.  When  rolls  are  used  at  the  break,  the  lead 
to  cover  them  requires  to  be  well  secured,  or  it  will  work 
loose  upon  the  rolls  and  probably  be  displaced  by  gales. 
There  are  simpler  methods  than  those  given  for  fixing  lead  on 
torus  rolls,  but  they  are  not  so  effective. 

A  fillet  is  provided  at  the  eave  of  the  higher  portion  of 
the  roof,  as  it  is  imperative  that  the  slates  be  firmly  laid  if 
they  are  to  be  prevented  from  dislodgment  in  boisterous 
weather.  At  A,  Fig.  37,  the  apron  flashing  is  first  fixed  in 
position ;  then  the  lead  which  covers  the  roll  and  is  turned 
on  the  upper  roof  is  secured  along  the  top  of  the  first  flashing  ; 
the  wood  roll  is  afterwards  fixed,  and  the  last  piece  of  lead 
is  turned  upwards  and  over  the  roll,  the  lead  being  made 
secure  by  nailing  it  along  its  top  edge.  This  method  of 
covering  a  torus  roll  will  not  be  suitable  for  every  case,  and 
unless. the  lead  is  fixed  in  comparatively  short  lengths  there 
will  be  trouble  in  getting  it  tight  on  the  roll. 

A  different  but  good  method  of  covering  torus  rolls  is 
indicated  by  B,  Fig.  37,  but  it  takes  a  little  more  lead  than 
that  given  at  A.  The  apron  flashing,  as  before,  is  placed  first 
in  position,  and  on  that  a  narrower  strip  is  fixed  for  the 
whole  length  of  the  roll.  The  wood  roll  is  then  secured  in 
position,  and  is  covered  by  another  piece  of  lead  which  is 
fixed  on  the  higher  roof.  The  strip  of  lead  immediately  at 
the  back  of  the  roll  is  turned  forward  under  it,  and  with 
this  strip  and  the  lead  which  covers  the  upper  part  of  the 


ROOF   WORK 


69 


roll  a  clinked  or  welted  joint  is  formed.     To  obviate  a  large 
bulge  being  formed  along  the  bottom  of  the  roll,  the  strip  of 


FIG.  37.— Treatment  of  "torus  rolls"  or  "bottles"  when 
in  exposed  situations. 

lead  immediately  behind  the  roll  is  usually  thinner  than  the 
remaining  part  of  the  lead. 


70       DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

When  rolls  are  omitted,  a  simple  but  effective  method  of 
fixing  the  lead  flashings  is  that  illustrated  at  0,  Fig.  37. 

Turret  Roofs. — The  leadwork  in  connection  with  turret 
roofs  is  often  of  an  intricate  nature,  and  especially  when  the 
turrets  take  a  very  ornamental  form.  It  is  advisable  to 
keep  the  pieces  of  lead  as  small  as  practicable,  as  they  can  be 
the  more  readily  fixed  and  secured  than  large  pieces. 

Fig.  38  shows  a  ventilating  turret  which  is  located  at  the 
top  of  a  span  roof.  At  the  base  it  is  square  on  plan,  whilst  the 
louvred  portion  and  roof  take  a  hexagonal  form.  For  covering 
the  lower  and  plain  part  of  the  structure,  the  lead  may  be 
arranged  in  vertical  bays  as  shown,  the  pieces  being  joined 
with  clinked  or  welted  joints.  Copper  ties  would  be 
necessary  both  along  the  bottom  edge  of  each  bay  and  in  the 
seams  for  securing  the  leadwork.  Before  the  bays  are  formed 
the  apron  A  and  flashings  G-  would  of  course  be  placed  in 
position.  If  a  bolder  joint  for  the  vertical  bays  is  required, 
hollow  rolls  can  be  made  in  lieu  of  the  flat  seam.  To  fix 
lead  on  vertical  surfaces,  as  at  B,  Fig.  38,  hollow  rolls  are 
superior  to  solid  ones.  If,  on  the  other  hand,  the  rolls 
were  diagonally  arranged,  solid  rolls  would  be  preferable, 
and  the  work  could  be  executed  much  more  quickly  thair 
if  hollow  rolls  were  adopted.  The  lead  flashings  between 
the  bays  B  and  the  cornice  C  may  be  covered  in  a  number 
of  pieces  as  shown. 

Each  section  of  the  cornice  C  should  be  covered  separately, 
and  the  lead  well  set  in  to  take  the  correct  shape  of  the 
moulding,  and  trimmed  off  as  in  Fig.  38.  For  joining  two 
pieces  of  lead  on  the  cornice,  clinked  or  welted  seams  may 
be  used,  the  latter  being  formed  on  one  side  a  little  removed 
from  the  mitre. 

To  cover  a  turret  roof,  such  as  that  in  Fig.  38,  either 
solid  or  hollow  rolls  may  be  adopted,  the  latter  being 
preferable  for  the  shape  given.  In  the  Fig.  it  will  be 
observed  that  the  rolls  are  nearly  vertical  for  a  portion  of 
their  length.  If  solid  rolls  are  used  in  such  cases  it  is 
desirable  that  each  bay  be  supported  with  secret  ties  in 
addition  to  the  usual  fixings  on  the  vertical  parts.  The  lead 
covering  the  cornice  C  is  continued  up  the  roof  for  a  distance 


ROOF   WORK 


71 


FIG.  38. — Method  of  covering  turret  with  sheet  lead. 

of  say  5  iDches,  so  that  the  rolls  and  bottom  edge  of  the 
roof  bays  may  be  trimmed  clear  of  the  cornice.     The  upper 


72      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

end  of  the  rolls  are  capped  with  the  lead  which  covers  the 
base  of  the  finial. 

On  large  turret  roofs  intermediate  rolls  would  be  required, 
and  many  of  the  bays  may  require  to  be  covered  with  two  or 
more  pieces  of  lead. 

Shape  of  Bays. — In  practice,  the  shape  of  the  lead  for 
covering  a  bay  on  a  turret  roof  is  not  a  very  difficult  matter 
to  obtain.  A  simple  method  of  determining  the  true  shape 
is  as  follows :  First  strike  a  line  from  top  to  bottom  down 
the  centre  of  the  bay.  At  right  angles  to  the  centre  line 
set  off  a  number  of  other  lines  on  the  whole  length  of  the 
bay,  at  convenient  distances  apart.  The  closer  the  parallel 
lines  are  together  the  better,  but  6  to  12  inches  apart, 
depending  upon  the  size  and  shape  of  the  turret,  will,  as  a 
rule,  be  suitable  for  general  work.  All  the  lines  should 
now  be  measured  and  their  lengths  noted.  It  will  be  found 
convenient,  if  a  rough  sketch  of  the  bay  is  made  in  a  pocket- 
book  or  on  a  piece  of  wood,  to  show  all  the  lines  which  have 
been  struck  upon  the  roof,  together  with  their  lengths.  The 
centre  line  over  the  curved  or  irregular  surface  may  be 
measured  with  a  tape.  All  the  lines  are  reproduced  on  a 
suitable  piece  of  lead,  and  their  exact  lengths  marked  off. 
Through  the  measured  points  on  the  parallel  lines  freehand 
lines  may  be  drawn,  when  the  shape  of  the  bay  will  be 
obtained.  The  allowance  of  lead  for  the  rolls  or  other  laps 
is  afterwards  added. 

When  the  shape  of  one  bay  has  been  produced,  it  is  used 
as  a  template  for  the  remaining  bays ;  corrections,  however, 
may  be  necessary,  as  the  dimensions  of  similar  parts  of 
different  bays  often  vary  slightly. 

Frequently  the  shape  of  half  a  bay  is  obtained  in  the 
manner  above  described,  and  cut  out  in  either  zinc  or  thin 
sheet  lead ;  this  is  simply  used  as  a  template  for  the  other 
bays,  and  admits  of  any  little  alteration  being  readily  made. 
As  before,  the  allowance  for  laps  and  rolls  is  afterwards 
added. 

When  the  shape  of  a  bay  for  a  turret  or  similar  roof 
requires  to  be  produced  from  drawings,  the  exact  dimensions 
may  not  admit  of  direct  measurement,  see  Fig.  39.  To 


ROOF    WORK 


73 


determine  the  shape   of   a   bay   in   this   case,  first  draw  to 

scale  a  part  section  and  plan  of 
the  structure,  as  A  and  B,  Fig.  39. 
Divide  the  curved  line  of  section 
A  into  any  given  number  of  parts, 
making  them  equal  as  far  as  pos- 
sible for  the  sake  of  simplicity ;  so 
far  as  exactness  is  concerned  the 
more  parts  into  which  the  line  is 
divided  the  better.  Next  set  off  a 
line  in  plan  B  at  right  angles  to 
the  centre  of  xy,  so  as  to  divide 
the  plan  of  one  bay  into  two  equal 
parts.  From  the  numbers  on  the 
curved  line  of  section  A,  drop  per- 
pendiculars  to  pass  through  the 
plan  as  in  B,  and  number  as 
shown.  Next  draw  a  line  mn  as 


IF          *  g    JL 

-f-f pg -tl 


n 

FIG.  39. — Method  of  obtaining  true  shape  of  lead  work  for  a  bay 

from  drawings. 


74      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

in  C,  Fig.  39,  and  at  right  angles  to  it  draw  a  number  of 
horizontal  lines  exactly  the  same  distance  apart  as  the 
divisions  on  the  curved  line  in  section  A,  and  number  in 
like  order.  The  widths  for  the  different  parts  of  the  bay 
are  obtained  from  the  plan  B  by  taking  the  distances  between 


FIG.  40.— Details  of  lead  for  turret  roofs. 

the  hips  and  reproducing  them  on  the  lines  with  like  numbers 
in  C.  Join  the  points  obtained  by  freehand  and  the  correct 
shape  or  development  will  be  obtained.  The  allowance  for 
rolls  is  then  added  and  is  represented  by  the  dotted  lines 
in  C. 

The  finial  at  the  apex  of  Fig.  38   may  be  covered  with 
three  pieces  of  lead  :  the  first  piece,  L,  caps  the  rolls  and 


ROOF   WORK 


75 


covers  the  base  of  the  finial ;  the  second  piece  covers  the 
ball  K,  and  the  third  the  top  part  H. 

Details  of  Turret  Roofs. — Fig.  40  gives  a  few  details  in 
connection  with  these  roofs.  At  A  is  illustrated  how  a 
plain  cornice  may  be  covered  ;  B  indicates  how  secret  ties 


FIG.  41. — Method  of  securing  leadwork  on  vertical  or  quick  pitched 
surfaces  with  solid  rolls. 


may  be  utilised  for  securing  rather  wide  pieces  of  lead, 
and  for  keeping  the  leadwork  close  to  the  boarding  where 
the  lead  tends  to  draw  or  fall  away.  The  ties  are  soldered 
on  the  under  side  of  the  lead,  and  they  can  be  either  screwed 
to  the  face  of  the  woodwork  or  passed  through  a  slot  and 
secured  inside  the  structure,  as  shown  in  B,  Fig.  40  ;  the 


76      DOMESTIC   SANITARY    ENGINEERING    AND   PLUMBING 

latter  method  makes  substantial  fixings  when  it  is  practicable 
to  adopt  it. 

A  cross  section  of  a  hollow  roll  and  copper  tie  is  given 
at  C,  Fig.  40. 

Domes. — The    lead  work  for   covering  domes   is  arranged 


FIG.  42. — Finial  covered  with  three  pieces  of  lead. 


and  set  out  in  a  similar  manner  to  that  given  for  turret 
roofs.  Solid  rolls  are  well  suited  for  hemispherical  domes, 
as  the  bays  gradually  increase  in  width  for  their  whole 
length ;  if  the  work  is  properly  carried  out  it  is  scarcely 
possible  for  the  bays  to  slip,  on  account  of  the  grip  the 
under  and  overcloaks  have  upon  the  rolls.  Wood  cores 
should  be  well  undercut  to  give  the  lead  a  firm  hold,  and  secret 


ROOF   WORK 


77 


fastenings  may  also    be  necessary  in    certain  cases    in    the 
widest  parts  of  the  bays. 

Covering  Vertical  Surfaces. — Fig.  41  shows  how  solid 
roll  work  may  be  carried  out  for  vertical  and  quick  pitched 
surfaces.  Instead  of  the  undercloaks  being  turned  over  the 
rolls  they  may  be  left  flat,  and  the  wood  rolls  planted  on  them 
and  screwed  down  as  shown  by  the  enlarged  detail  A.  When 


FIG.  43. — Method  of  obtaining  shape  of  lead  for  covering  centre 
part  of  Fig.  42. 

the  work  is  executed  in  this  way  the  undercloak  of  each 
bay  is  securely  held  in  position,  whilst  each  roll  also  forms 
a  substantial  support  for  the  bay  immediately  above.  The 
overcloaks  require  to  be  made  secure  by  copper  ties,  and 
the  rolls  may  often  be  cut  a  little  short  to  simplify  the 
work,  as  in  Fig.  41.  The  ordinary  method  of  treating  the 
undercloaks  is  neither  necessary  nor  suitable  for  vertical  or 
very  quick  pitched  surfaces.  The  bays  should  be  kept  as 
narrow  as  possible,  especially  for  vertical  surfaces. 


78      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

Finials. — These  take  a  large  variety  of  forms,  and  the 
methods  of  covering  them  will  depend  upon  their  size  and 
shape.  A  simple  form  of  finial  which  is  situated  at  the 
apex  of  a  conical  shaped  roof  is  given  in  Fig.  42.  The 
flashing  which  covers  the  upper  ends  of  the  slates,  and  also 
that  which  covers  the  trunk  of  the  finial,  represent  frustums 
of  cones. 

A  simple  method  of  obtaining  the  development  of  a 
frustum  of  a  cone  sufficiently  accurate  for  practical  work  is 
shown  in  Fig.  43.  First  draw  an  exact  section  of  the 
frustum  under  consideration,  say  bcedb,  and  prolong  lines 


FIG.  44. — Shape  of  lead  for  covering  base  of  Fig.  42. 

db  and  ec  until  they  meet  as  a.  With  a  as  centre  and 
radius  ad  describe  the  arc  rs ;  with  the  same  centre  and 
radius  ab  describe  the  upper  arc  tu.  On  rs  point  off  the 
distances  dff  and  el,  making  each  equal  to  de.  From  H  and 
I  draw  lines  to  a,  cutting  the  arc  tu  at  K  and  L,  when 
KLIHK  will  be  the  development  required.  Allowance  for 
laps  or  joints  must  then  be  added,  as  shown  by  dotted  lines. 

In  Fig.  42  the  lead  which  covers  the  lower  frustum  is 
carried  up  a  few  inches  on  the  trunk  which  forms  the 
higher  frustum ;  as  these  have  different  pitches,  an  allowance 
must  be  made,  as  shown  by  the  curved  dotted  line  in  Fig.  44, 
otherwise  the  lead  forming  the  lower  frustum  will  not  girt 
the  trunk  of  Fig.  42  where  the  overlap  occurs.  After  the 


ROOF    WORK 


79 


lead  of  the  shape  Fig.  44  is  cut  out,  it  can  be  bent  round 
the  structure,  excepting  the  allowance  for  the  overlap,  which 
will  require  to  be  bossed  into  position,  and  any  surplus  lead 
can  afterwards  be  cut  off.  After  the  first  two  pieces  of 
lead  for  Fig.  42  are  in  position,  the  top  may  be  covered  by 
bossing  a  circular  piece  of  lead  in  the  { 

form  of  a  cup,  and  afterwards  finishing 
it  in  its  place. 

Finials  which  are  comparatively 
small  in  size  are  occasionally  covered 
with  one  piece  of  lead,  which  is  bossed 
to  something  like  the  shape  required  and 
afterwards  completed  in  its  place. 

In  other  cases,  where  a  simple  form 
of  finial  is  to  be  covered,  the  approxi- 
mate development  is  cut,  when  the  lead 
is  partly  bent  and  partly  worked  into 
its  place.  Care,  however,  in  these  cases 
requires  to  be  taken  when  setting  out 
the  lead,  so  as  to  have  it  sufficiently 
large  at  all  parts. 

Where  finials  are  built  up  in  sections, 
and  are  held  together  by  iron  rods  pass- 
ing through  them,  the  upper  parts  can 
be  removed,  whilst  those  immediately 
beneath  receive  attention. 

Finial  Fig.  45  is  shown  with  a 
circular  base,  and  is  covered  with  five 
pieces  of  lead.  For  the  base  A  the  lead 
may  be  roughly  bossed  to  the  required 
shape  and  finished  in  position.  Should 
the  base  A  be  square  on  plan,  it  would 
be  easier  to  cover  this  part  with  four 
pieces  of  lead  with  joints  formed  at  the  angles.  The  part  B 
can  be  dealt  with  by  bossing  the  piece  of  lead  dome-shaped, 
and  finishing  it  off  as  shown.  The  small  column  C  may 
either  be  covered  with  a  piece  of  lead  pipe  or  sheet  lead 
suitably  formed,  whilst  the  ball  D  may  be  covered  as  before 
described,  and  trimmed  off  about  3  inches  down  on  column  C. 


FIG.  45.— Fiuial. 


80       DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

For  covering  the  conical  part  e  a  piece  of  pipe  may  be 
dressed  to  the  shape  required,  or  it  may  be  covered  with 
sheet  lead,  the  edges  of  which  are  joined  by  burning  or  by 
other  suitable  means. 

TABLE  I. 

STRENGTHS  OF  LEAD  FOR  ROOF  WORK 

Gutters  .        .        ;        ;  «  .  .  5  to  7  Ib.  per  sq.  foot. 

Flats       .         ...  .  ,.:  •  ,,  6  to  8   „         „        „ 

General  flashings     .         .  .  .  .  4  to  7   ,,        ,,        ,, 

Under  flashings  or  soakers  .  ;  .  3  to  5   ,,        ,,        ,, 

Hip  soakers     .         3    :     .  .  .  .  2  to  3    ,,         ,,         ,, 


CHAPTEK    III 
PIPE   FIXING   AND   PIPE  BENDING 

THE  methods  of  supporting  and  fixing  pipes  are  chiefly 
determined  by  the  metal  of  which  they  are  made,  the 
purposes  for  which  they  are  to  be  used,  the  situation  in 
which  they  are  to  be  placed,  the  kind  of  structure  to  which 
they  require  to  be  fixed,  and  the  size  of  the  pipes. 

The  old  method  of  burying  small  pipes  in  the  plaster- 
work  of  walls  is  fast  becoming  obsolete  on  account  of  the 
inaccessibility  of  the  pipes  and  the  damage  done  when 
repairs  require  to  be  effected.  Most  of  the  important  pipes 
in  modern  buildings  are  fixed  either  in  exposed  positions 
or  in  accessible  situations.  Of  course  special  cases  do  occur 
in  buildings  where  certain  pipes  cannot  be  made  readily 
accessible,  but  when  fixed  in  such  positions  extra  precautions 
should  be  taken  to  prevent  the  pipes  failing  at  these  points. 

On  plastered  walls  lead  water  pipes  are  frequently  fixed 
to  wood  grounds,  and  the  pipes  can  be  neatly  and  readily 
secured.  Where  cheap  fixings  are  necessary  either  malleable 
or  tinned  iron  clips  can  be  used.  Lead  clips  are  not  suitable 
for  taking  the  weight  of  a  pipe,  unless  they  are  strongly 
made  and  soldered  to  the  pipes.  Cast  lead  lugs,  when 
soldered  to  the  back  of  pipes,  make  substantial  fixings,  and 
many  have  a  neat  appearance. 

Although  lead  clips  and  lugs  can  be  readily  procured 
many  plumbers  prefer  to  make  them.  After  a  suitable 
design  has  been  decided  upon,  a  pattern  of  the  lug  or  clip 
requires  to  be  made,  when  a  cheap  mould  may  be  formed  in 
either  plaster  or  lead. 

When    numerous   fixings  are  required  it   is   better  and 
cheaper  in  the  long  run  to  procure  gun-metal  or  iron  moulds. 
6 


82      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


SOLDER 


Plaster  moulds  are  readily  chipped,  and  their  life  is  com- 
paratively short,  but  new  ones,  of  course,  can  be  readily 
made.  These  moulds  require  to  be  slowly  and  thoroughly 
dried  before  use  if  sound  castings  are  to  be  produced.  Lead 
moulds  with  care  are  fairly  durable,  but  after  a  number  of 
castings  have  been  made  they  get  rough,  when  much  time 
is  taken  in  trimming  them  to  make  them  moderately  smooth. 
Before  running  molten  lead  into  lead  moulds  the  latter  should 
be  well  smeared  with  plumbers'  black.  Clips  or  lugs  on 
small  vertical  lead  pipes  should  be  fixed  about  2  feet  apart, 
and  a  little  closer  on  horizontal  pipes. 

Wood  Grounds  are  sometimes  fin- 
ished flush  with  the  plaster-work  of 
walls,  but  they  are  better  when  fixed 
on  the  face  of  the  plaster ;  in  the  first 
case  the  plaster  is  liable  to  crack  and 
to  leave  the  edges  of  the  boards,  either 
by  the  latter  shrinking  or  by  jarring 
the  boards  when  fixing  the  pipes. 
Lead  pipes  which  are  horizontally 
•SOLDER  arranged,  and  convey  hot  water,  should 
be  supported  on  wood  fillets. 

When  lead  clips  are  used  for 
securing  long  lead  waste  pipes  which 
are  alternately  heated  and  cooled,  the 
clips  should  not  be  soldered  to  the  pipes, 
or  the  latter  would  be  held  too  rigid. 
By  the  use  of  iron  hooks  lead  pipes  are  often  distorted 
or  bruised,  but  this  can  be  avoided  to  a  great  extent  by 
placing  a  strip  of  sheet  lead  about  j  inch  in  width  between 
the  pipes  and  heads  of  the  hooks.  Iron  hooks  as  a  rule 
are  not  satisfactory  fixings  for  lead  pipes,  but  of  course  they 
possess  the  advantage  of  comparative  cheapness. 

Large  Lead  Pipes. — The  fixings  for  lead  soil  pipes  and 
rain-water  pipes  may  take  the  form  of  cast  lead  sockets, 
plain  or  ornamental  lugs  or  tacks,  iron  brackets,  and  lead 
flanges,  etc.  In  Fig.  46  a  cast  lead  socket  is  shown  ;  it  is 
sufficiently  large  to  slip  over  the  pipe,  and  it  is  secured  by 
soldering  at  both  ends  to  the  pipe  as  shown.  Sockets  make 


FIG.  46. — Lead  socket 
soldered  to  pipe. 


PIPE    FIXING    AND    PIPE    BENDING 


83 


good  and  substantial  fixings  when  fixed  at  suitable  distances 
apart.  Sheet  lead  tacks,  Fig.  47,  only  support  a  pipe  at  the 
back ;  they  are  usually  soldered  as  shown,  to  enable  a  pipe  to 
tit  close  to  a  wall,  but  the  soldering  may  be  done  at  the  front 
of  the  tacks  if  desired.  When  plain  tacks  are  used,  they  are 
frequently  made  sufficiently  wide  to  enable  the  nail  heads  to 
be  covered  by  doubling  part  of  the  tack  over  and  dressing  it 
down,  as  indicated  on  the  right  side  of  Fig.  47. 


SOLDER 


SOLDER 


FIG.  47.— Plain  lead 
tacks. 


FIG.  48. — Ornamental  lugs 
or  tacks. 


Ornamental  lugs  or  tacks,  Fig.  48,  are  cast  in  moulds. 
Cast  tacks  make  better  fixings  than  those  made  from  sheet 
lead,  as  they  are  thicker  and  stronger ;  they  are  soldered  to 
the  back  of  the  pipes,  so  that  no  solder  is  exposed  to  view. 

When  tacks  are  in  pairs,  as  shown  in  Figs.  47  and  48, 
they  are  usually  fixed  to  5  feet  centres  on  10  feet  lengths  of 
pipe,  and  to  4  feet  centres  on  1 2  feet  lengths,  the  latter  being 
the  more  suitable  distance  apart.  If  single  tacks  are  used 
they  should  be  half  the  above  distances  apart,  and  fixed 
alternately  on  both  sides  of  the  pipes.  Not  less  than  two 


84      DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 


nails  should  be  used  for  each  tack ;  for  brick  walls  the  nails 
would  be  the  same  distance  apart  as  the  joints,  and  for  stone 
walls  they  should  not  exceed  4  inches  apart.  The  minimum 
width  of  lead  tacks  for  large  pipes  should  be  6  inches. 

Ornamental  fixings,  as  in  Fig.  49,  may  be  formed  from  one 
piece  of  sheet  lead  if  desired.  In  this  case,  after  the  piece  of 
lead  has  been  cut  to  the  required  width,  the  astragals  may  be 

formed  by  driving  the  lead  into 
grooves  in  an  oak  block  by 
means  of  a  blunt  chase  wedge  or 
by  other  suitable  tool.  The  lugs 
or  ears  may  then  be  cut  to  the 
required  design,  when  the  centre 
portion  may  be  formed  by  bend- 
ing it  round  a  wood  mandril  or 
length  of  iron  pipe.  Should 
scroll  ears  be  adopted,  as  in  Fig. 
49,  these  can  now  be  shaped,  and 
the  whole  afterwards  soldered  to 
the  pipe  down  the  back  and  round 
both  astragals.  The  star  or  other 
ornamentation  could  either  be 
cast,  or  cut  from  sheet  lead  and 
sweated  on  with  solder.  If 
desired  the  star  may  be  carved 
out  in  the  piece  of  oak  on  which 
the  astragals  were  made,  and 
formed  by  bossing  the  lead  into  it. 
Fixings  for  square  lead  pipes 
are  often  of  an  ornamental 


FIG.  49. — Ornamental  fixings. 


character,  but  as  these  pipes  are  chiefly  used  for  discharging 
rain  water  from  the  roofs  of  buildings,  the  upper  end  of  each 
length  of  pipe  is  prepared  to  serve  as  both  joint  and  fixing. 
Socketed  joints  for  square  lead  pipes  are  sometimes  formed 
as  in  Fig.  50,  where  a  spiggot  piece  is  inserted  and  soldered 
to  the  pipe.  The  astragals  and  tacks  are  separately  put  on, 
and  intermediate  fixings  are  arranged  in  the  same  manner 
excepting  that  the  slip  joint  is  absent. 

Sockets   for    square    lead   pipes   are   much   better  when 


PIPE    FIXING    AND    PIPE   BENDING 


85 


separately  cast,  as  they  can  be  made  larger  than  the  pipes, 
and  the  contractions  at  the  joints,  as  in  Fig.  50,  dispensed 
with. 

Where  large  lead  pipes  are  fixed  in  chases  or  recesses 
inside  buildings,  the  simplest  means  of  supporting  them*  is 
shown  in  Fig.  51.  The  worst  feature  with  regard  to  chases 
is  that  they  are  seldom  large  enough,  so  that  the  pipes  are 
not  so  accessible  as  they  should  be.  Flange  fixings,  Fig.  51, 
can  often  be  adopted  where  pipes  pass  through  floors. 

Iron  and  Copper  pipes,  owing  to  their  rigidity,  can  be  fixed 


FIG.  50.— Slip  joint  and 
ornamental  fixing. 


FIG.  51. — Flange  support  for 
pipe. 


in  a  different  manner  from  lead  pipes.  Small  iron  pipes 
when  fixed  to  woodwork  may  be  secured  by  clips  in  the 
ordinary  manner,  but  they  do  not  require  to  be  so  closely 
together  as  for  lead  pipes. 

A  convenient  form  of  hanger  for  fixing  a  pipe  beneath  a 
ceiling  is  illustrated  in  Fig.  52.  The  loop  that  directly 
supports  the  pipe  is  made  in  two  parts,  and  bolted  together 
as  shown. 

Another  hanger  suitable  for  fixing  to  a  steel  girder  is 
given  in  Fig.  53  ;  this  has  a  swivel  joint  which  enables  the 
pipe  to  be  placed  in  any  position  relative  to  the  girder. 


86       DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


Hangers  like  Figs.  52  and  53  are  made  in  malleable  iron,  and 
are  comparatively  cheap. 

Since  silver-plated  and  lacquered  copper  pipes  have  come 
into  more  general  use  in  good  buildings  for  waste  and  service 
pipes  in  connection  with  sanitary  fittings,  these  pipes  are 
frequently  fixed  clear  of  walls  so  as  to  admit  of  their  being 
readily  kept  clean.  Two  neat  forms  of  brass  fixings  for  light 
copper  pipes  are  given  in  Fig.  54.  That  at  A  is  suitable  for 
brick  and  stone  walls,  and  the  one  at  B  for  fixing  to  wood- 


FIG.  52.— Pipe  hanger. 


FIG.  53. — Pipe  hanger  with 
swivel  joint. 


work.  The  part  which  grips  the  pipe  is  made  in  two  parts, 
and  is  neatly  joined  at  the  front  and  shoulder  as  shown.  A 
small  dowel  keeps  the  movable  part  of  the  clip  in  position 
at  the  front,  whilst  at  the  shoulder  a  set  screw  is  used. 

Cast  iron  brackets  make  good  fixings  for  heavy  iron 
pipes  where  the  latter  require  to  be  made  secure  along  the 
face  of  a  wall. 

Fig.  55  gives  a  roller  bracket  for  supporting  steam  or  hot- 
water  pipes  along  a  corridor  or  similar  wall. 

Another  roller  fixing,  Fig.  56,  may  be  suitable  for 
supporting  large  steam  or  hot-water  pipes  when  fixed  in  a 


PIPE    FIXING    AND    PIPE   BENDING 


87 


subway  or  passage  clear  of  the  walls.  In  this  case  the  roller 
is  supported  on  a  light  steel  girder,  which  is  fixed  across  the 
opening.  Koller  fixings  may  also  be  readily  designed  for 
securing  pipes  beneath  girders,  and  in  other  situations,  when 
it  is  found  advantageous  to  do  so. 

Bending  Pipes. — The  method  of  forming  bends  on  lead 
pipes  is  regulated  to  a  great  extent  by  their  size,  by  the 
radius  of  the  bends,  and  by  the  thickness  of  the  pipes. 

Bends  should  be  made  as  easy  as  practicable,  for  when 


FIG.  54. — FixiDgs  for  light  copper  pipes. 

sharp  they  unnecessarily  retard  the  flow  of  liquids  and  gases 
through  them ;  the  metal  is  also  unduly  strained  during  the 
bending  process,  and  in  the  case  of  pipes  of  large  diameter 
quick  bends  take  longer  to  make. 

Springs  are  largely  used  for  preserving  a  uniform  bore 
when  bending  lead  pipes,  and  they  answer  very  well  for  pipes 
up  to  1 J  inches  diameter,  when  the  bends  are  gradually  made. 
Bends  can  also  be  made  in  2  to  2^  inch  lead  pipes  with  the 
aid  of  springs,  but  when  these  pipes  are  thin  the  back  of  the 
bends  is  considerably  reduced  in  substance,  and  occasionally 
torn. 


88      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


FIG.  55.— Roller  bracket. 


Before  a  spring  is  inserted  in  a  lead  pipe  the  latter  should 
first  be  properly  straightened,  and  all  kinks  or  irregularities 
removed  by  driving  a  bobbin  or  short   mandril  through  it. 
When  a  bend  is  made  on  thin  pipes  the 
sides  bulge  out  a  little,  and  these  should 
be  carefully  dressed  to  send  the  surplus 
lead    towards   the  back    of   the  bend. 
The  spring  can  then  be  withdrawn  by 

ffa^^^^rW////////Ji  twisting  to  reduce  its  size  and  by 
3  |t5Sj:^§|^^  giving  a  PUU  at  tne  same  time-  The 
twisting  of  the  spring  is  not  always 
necessary,  and  a  steady  pull  will  usually 
suffice  to  withdraw  it  provided  the  pipe 
has  been  properly  prepared  and  the 
bend  carefully  made. 

Many  plumbers  are  too  rough  with 
springs,  and  very  quickly  strain  them 
by  either  twisting  them  the  wrong  way 
prior  to  withdrawal,  or  by  getting  them 

fast  in  the  pipes.  In  a  thin  lead  pipe  a  spring  does  not 
prevent  a  small  buckle  forming  at  the  throat  when  a  bend 
is  carelessly  made ;  should  an  attempt  be  made  to  remove 
such  buckle  by  dressing  up  the  bend  with  the  spring  still 
inside,  the  inner 
surface  of  the  pipe 
will  conform  with 
that  of  the  spring  ; 
under  such  circum- 
stances the  spring 
is  fastened  in  the 
pipe,  and  can  only 
be  withdrawn  by 
the  application  of 
considerable  force. 
Bends  in  2  to 

2-J-inch  light  lead  pipe  are  better  made  in  several  stages,  and 
at  each  step  the  bends  should  be  brought  to  their  normal  dia- 
meters by  drawing  or  driving  bobbins  through  them.  A  small 
dummy  may  also  be  used  when  bending  a  2J-inch  pipe. 


FIG.  56.— Roller  fixing. 


PIPE    FIXING    AND    PIPE    BENDING  89 

Slow  bends  can  often  be  made  on  light  lead  pipes  of  1-J 
inches  diameter  and  less  by  first  slightly  flattening  the  sides 
of  the  pipes  where  the  bends  are  to  be  formed.  The  effect  of 
bending  is  to  push  outwards  the  flattened  parts,  when  the 
bends  can  afterwards  be  dressed  to  the  required  size.  Bends 
may  also  be  easily  made  on  lead  pipe  up  to  2  inches  diameter 
after  loading  them  with  fine  sand.  Flush  and  waste  pipes 
can  be  neatly  and  quickly  bent  with  the  aid  of  sand,  especially 
when  the  latter  is  warm.  Prior  to  bending,  the  pipes  must  be 
well  filled  with  sand,  and  their  ends  plugged  to  prevent  any 
sand  escaping  whilst  the  bends  are  being  made.  Bends  made 
with  the  aid  of  sand  are  preferable  to  those  in  which  springs 
are  used,  as  the  inner  surfaces  in  the  latter  case  are  corru- 
gated with  the  springs. 

Bending  Large  Pipes. — When  bending  lead  pipes  whose 
diameters  exceed  2^-  inches,  dummies  are  generally  used. 
Large  pipes  flatten  and  buckle  much  more  readily  than  small 
pipes  when  bent,  and  in  order  to  strengthen  the  back  of 
bends  the  superfluous  lead  which  gathers  at  the  sides  should 
be  driven  towards  that  point. 

Before  bending  large  pipes  a  short  mandril  about  1  foot 
in  length  should  be  driven  through  them  to  remove  all  irregu- 
larities, and  also  to  straighten  them.  An  ordinary  bobbin 
does  not  straighten  pipes  when  driven  through  them,  but 
simply  removes  the  creases  or  indentations. 

To  make  a  bend  of  90°  on  a  length  of  4 -inch  lead  pipe, 
not  less  than  five  stages  of  bending  should  be  necessary,  and 
each  time  the  pipe  is  bent  it  should  be  worked  to  take  its 
true  form.  A  square  bend  may  be  made  with  less  than  five 
bending  stages,  but  the  lead  is  not  so  easily  and  well  dis- 
tributed when  the  bend  is  made  with  less.  At  the  point 
where  the  bend  is  to  be  made  the  pipe  may  be  heated  with  a 
Swedish  torch,  or  by  other  means,  to  a  temperature  of  about 
220°  F.,  but  the  back  of  the  bend  should  be  kept  as  cold  as 
practicable.  The  usual  plan  when  pulling  up  the  pipe  is  to 
place  the  knee  at  the  point  where  the  bend  is  wanted,  a  piece 
of  felt  or  other  material  being  used  to  protect  the  knee  from 
the  heat.  If  the  bend  is  near  the  end  of  the  pipe  the 
necessary  leverage  can  be  obtained  by  the  aid  of  a  mandril. 


90        DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

As  the  pipe  is  bent  it  will  flatten  considerably,  and  from 
this  point  either  of  the  two  following  methods  of  pro- 
cedure can  be  adopted.  The  first  method  is  to  turn  the 
partially  made  bend  on  one  side,  whilst  the  opposite  side  is 
smartly  struck  with  a  suitable  dresser  to  drive  the  lead 
towards  the  back  of  the  bend ;  the  opposite  side  is  treated 
afterwards  in  the  same  manner.  The  flattening  of  the 
bulged- out  sides  makes  more  room  in  the  bend  for  working 
the  dummy,  but  it  possesses  the  drawback  of  forming  a  hard 
ridge  on  each  side  of  the  throat.  In  the  second  method, 
instead  of  driving  the  lead  from  the  sides  of  the  bend  the 
throat  is  worked  up,  and  after  this  is  done  the  superfluous 
lead  is  then  driven  from  the  sides  to  the  back  as  before 
described.  In  the  latter  method  of  procedure  there  is  less 
space  when  beginning  to  dummy  up  the  throat,  but  there  is 
ample  space  if  the  bend  is  not  pulled  up  too  much  at  one 
time.  It  possesses  one  advantage  in  that  hard  ridges  are 
less  likely  to  be  formed. 

When  dressing  the  material  towards  the  back  of  a  bend 
there  is  a  tendency  for  the  latter  to  straighten  out,  and  this 
is  especially  pronounced  when  the  bend  is  near  the  end  of  a 
pipe.  The  straightening  of  the  bend,  however,  should  be  pre- 
vented as  far  as  possible  so  as  to  avoid  unnecessary  labour. 
At  each  stage  after  the  bend  is  dummied  into  shape  a  bobbin 
should  be  passed  round  it,  to  remove  any  irregularities  and 
to  make  the  bend  of  uniform  bore.  Bobbins  are  passed  round 
bends  by  the  application  of  force  either  at  the  front  or  behind 
them. 

To  drive  a  bobbin  round  a  bend  a  metal  weight  is  caused 
to  strike  it ;  the  weight  is  made  secure  in  the  middle  of  a 
strong  rope,  and  one  end  of  the  latter  is  passed  through  a 
central  hole  in  the  bobbin  ;  the  weight  is  then  drawn  forwards 
and  backwards  so  as  to  sharply  strike  the  bobbin.  Two 
persons  are  necessary  to  operate  the  weight,  as  the  rope  must 
be  kept  fairly  taut  or  the  weight  is  liable  to  knock  against 
and  disfigure  the  bend. 

When  force  is  applied  at  the  front  of  a  bobbin  no  weight 
is  used,  but  the  bobbin  is  either  simply  jerked  along  a  little 
at  a  time,  by  twisting  the  rope  round  a  hammer  shaft  or 


PIPE   FIXING   AND    PIPE   BENDING  91 

other  tool,  so  as  not  to  bruise  the  hand,  or  it  is  drawn  round 
a  bend  by  a  steady  pull,  when  the  necessary  power  is  obtained 
by  the  aid  of  a  suitable  winch.  As  regards  the  shape  of  a 
bobbin  for  drawing  through  pipes,  it  should  resemble  that  of 
a  pear  in  order  to  offer  the  minimum  resistance  against  the 
sides  of  the  pipes.  In  this  case  the  hole  in  a  bobbin  is  made 
in  a  lateral  direction  near  the  front,  so  as  to  enable  both  ends 
of  the  rope  to  be  pulled  in  the  same  direction  when  drawing 
a  bobbin  through  a  pipe. 

Weights  for  driving  bobbins  through  pipes  are  often  made 
of  plumbers'  solder,  and  these  answer  fairly  well  and  are 
easily  obtained.  Lead,  of  course,  is  too  soft  when  used  alone 
for  weights.  Brass  weights  may  also  be  obtained,  and  some 
have  leather  washers  arranged  to  protect  the  sides  of  the 
bends  from  being  bruised  when  in  use. 

Dummies. — To  form  dummies,  solder  ends  are  often  cast 
on  steel  rods  and  Malacca  canes.  Canes  are  suitable  for 
straight  dummies  up  to  about  2  feet  in  length,  but  for 
greater  lengths,  and  where  the  ends  require  to  be  bent,  steel 
rods  of  f  inch  to  J  inch  diameter  are  used.  The  handles  of 
very  long  dummies  should  be  fairly  rigid,  and  may  be  a  little 
thicker  than  the  sizes  given.  On  each  steel  rod  two  ends 
are  usually  cast,  one  serving  as  a  handle  when  the  other  end 
is  in  use.  Double  ends  also  reduce  the  number  of  separate 
dummies,  as  the  ends  may  be  bent  to  different  pitches  and  also 
differ  a  little  in  shape.  A  good  general  shape  for  dummies  is 
that  of  an  egg,  but  this  can  be  modified  a  little  as  experience 
deems  necessary. 

Working  Drawings. — When  making  offsets  and  bends 
much  time  would  often  be  saved  if  full-sized  working 
drawings  were  made,  either  on  the  workshop  bench  or  on  the 
floor.  If,  for  example,  a  pipe  requires  to  be  bent  to  form 
an  offset  with  angles  as  in  Fig.  57,  a  full  size  and  accurate 
drawing  should  first  be  made,  and  the  pipe  can  then  be  bent 
to  the  drawing. 

With  a  chalk  line  or  straight-edge  set  off  the  vertical 
lines  AB,  whose  distance  apart  is  equal  to  the  external 
diameter  of  the  pipe ;  next  set  off  the  distance  between  lines 
AC  equal  to  the  offset  required,  and  make  lines  CD  parallel 


92      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

with  those  of  AB.  From  F,  or  other  suitable  point,  set  off 
the  angle  of  120°  with  a  large  protractor  and  produce  FH. 
Make  GL  parallel  with  FH  and  the  lines  the  same  distance 
apart  as  AB.  Draw  curves  to  complete  the  offset.  The  last 
bend  may  now  be  made.  From  M,  or  other  point,  draw  MO 


FIG.  57. — Working  drawing. 


so  that  DM0  makes  an  angle  of  135°;  draw  NP  parallel 
with  MO,  and  complete  the  curves  as  before.  The  pipe  can 
now  be  bent  to  the  drawing,  and  when  finished  the  plumber 
would  be  sure  that  it  would  fit  its  intended  place.  By  the 
use  of  working  drawings  pipes  can  be  cut  to  exact  lengths,  and 
the  ends  prepared  on  the  bench  ready  for  jointing  in  position. 


PIPE   FIXING    AND    PIPE   BENDING 


93 


Development  of  Elbow  Pipes. — Occasionally,  in  order  to 
test  a  candidate  with  regard  to  his  geometrical  knowledge, 
Examiners  of  Plumbers'  Work  require  a  development  of 
an  elbow  to  be  made.  Suppose,  for  example,  the  develop- 
ment of  an  elbow  similar  to  Fig.  58  is  required.  First  draw 
to  a  suitable  scale,  or  full  size  if  required,  a  section  of  the 
elbow,  giving  it  a  pitch  of  112J°.  Immediately  over  the 


FIG.  58. — Method  of  obtaining  shape  of  lead  to  make  an  elbow  pipe. 

vertical  section  of  the  pipe  draw  a  plan,  and  divide  the 
circumference  into  any  given  number  of  equal  parts  exceeding 
six ;  the  more  parts  into  which  the  circumference  is  divided 
the  better  the  development  will  be.  In  the  case  under 
consideration  the  circumference  is  divided  into  12  parts. 
To  do  this,  first  divide  the  circle  into  quadrants,  and  from 
the  points  say  1,  4,  7,  and  10,  with  the  same  radius  as 
that  of  the  circle,  describe  curves  to  cut  the  circumference. 
Number  as  shown.  From  the  points  obtained  drop  lines 


94      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


parallel  with  the  sides  of  the  pipe  to  intersect  with  XY, 
Fig.  58.  On  the  horizontal  line  KL  transfer  the  numbers 
1,  2,  3,  4,  etc.,  from  the  plan ;  make  them  the  same  distance 
apart,  and  drop  perpendiculars  equal  in  length  to  CYE,  which 
represents  the  longest  dimension  of  the  elbow.  From  the 
intersections  of  the  vertical  lines  with  XY  draw  dotted  lines 
parallel  with  KL  across  the  verticals  in  MNPOM.  Where 
the  dotted  lines  from  XY  cut  like  numbers  in  MNPOM 


FIG.  59. — Method  of  obtaining  shape  of  lead  for  making  an  elbow  of 
rectangular  section. 

those  are  points  in  the  development  of  the  angle.  It  will 
be  observed,  upon  reference  to  the  plan  in  Fig.  58,  that 
points  1  and  7  represent  opposite  sides  of  the  pipes,  and 
therefore  the  lines  1  and  7  in  MNPOM  are  of  equal 
length.  This  applies  also  to  other  points  on  the  plan, 
such  as  2  and  6,  3  and  5,  etc.  By  connecting  the  points 
by  freehand  the  upper  curved  line  in  MNPOM  is  formed, 
and  represents  the  development  of  one  half  the  angle.  The 
lower  curved  line  is  drawn  after  plotting  the  distances  from 
the  upper  to  the  lower  side  of  the  centre  line.  The  space 


PIPE    FIXING    AND    PIPE   BENDING  95 

between  the  curved  lines  is  that  which  requires  to  be  cut 
away  in  order  to  form  the  elbow  required.  The  order  of 
numbering  the  plan  should  be  governed  by  the  position  of 
the  joint,  and  in  Fig.  5  8  the  joint  is  shown  to  be  in  the 
centre  of  one  side. 

The  development  of  an  elbow  for  a  rectangular  pipe  is 
given  in  Fig.  59.  Number  the  plan  of  pipe  as  shown, 
starting  from  the  point  where  the  joint  is  to  be  made. 
On  AB  set  off  the  sides  of  the  pipe  to  agree  with  plan,  and 
number  in  like  order.  Make  the  vertical  lines  in  dehfd, 


FIG.  60. — Pipe  bending  machine  by  Ed.  Le  Bas  &  Co. 

Fig.  59,  equal  to  cyl.  From  point  1  on  plan  drop  a  line 
parallel  with  the  sides  of  pipe  to  cut  xy  in  the  section. 
From  the  three  points  in  xy  draw  lines  parallel  with  AB 
across  those  in  dehfd.  As  before,  where  the  dotted  hori- 
zontal lines  from  the  section  cut  like  numbers  in  dehfd,  these 
represent  points  in  the  development  of  half  the  angle.  Join 
the  points  as  shown  with  straight  lines,  and  plot  the  distances 
on  the  other  side  of  the  centre  line  and  complete  the 
development. 

Bending    Copper    Pipes. — Thin   copper   pipes  when  over 
\  inch    diameter   cannot  readily  be  bent   by  hand   without 


96      DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 

flattening  a  little,  unless  loading  is  resorted  to.  The 
principal  materials  for  loading  pipes  are  metallic  lead,  sand, 
resin,  and  pitch.  Lead  is  not  often  adopted  as  it  is  more 
troublesome  to  use  than  the  other  materials  named. 

Sand  may  be  used  for  slow  bends  on  the  smaller  sizes  of 
pipes,  but  the  ends  of  the  pipe  require  to  be  well  plugged 
to  prevent  the  sand  escaping  when  forming  the  bends.  For 
making  quick  bends  resin  may  be  used,  and  it  can  be 
readily  melted  out  when  the  bends  have  been  made. 

Pitch,  either  alone  or  in  conjunction  with  resin,  is 
largely  used  for  bending  both  large  and  small  copper  pipes. 
It  is  only  necessary  when  using  the  two  latter  materials  to 
load  the  pipes  short  distances  past  the  parts  where  the  bends 
are  to  be  made.  Resin  and  pitch  are  melted  for  loading 
purposes,  and  a  paper  or  other  suitable  plug  may  be  used 
for  preventing  them  flowing  past  the  points  required. 

The  bending  of  light  copper  pipes  may  be  done  in 
different  ways,  but  where  many  bends  require  to  be  made, 
bending  machines  are  desirable  appliances,  and  much  time 
is  saved  by  their  use.  Fig.  60  illustrates  a  machine  which 
is  made  in  nine  different  sizes,  and  can  be  used  for  making 
bends  on  iron,  brass,  or  copper  tubes,  up  to  3  inches  in 
diameter.  The  upper  bend  in  the  illustration  has  a  flattened 
appearance,  but  that  is  due  to  defective  shading. 

For  making  an  occasional  bend  on  a  copper  pipe  a 
hole  in  a  plank  will  suffice ;  the  sharp  edges  should  be 
removed,  and  after  loading  the  pipe  the  latter  can  be  passed 
through  the  hole,  when  the  bend  may  be  gradually  turned. 
If  the  pipe  should  flatten  a  little  during  bending,  the  bend 
may  be  rounded  up  either  with  a  hard  dresser  or  round- 
faced  hammer. 

Copper  pipes  are  occasionally  found  to  be  hard,  and 
are  often  softened  before  being  bent.  To  soften  copper 
pipes  they  are  frequently  heated  to  redness  and  suddenly 
cooled.  Brittleness  is  frequently  due  to  the  pipes  not  being 
properly  annealed. 


CHAPTER    IV 
PIPE   JOINTS 

THE  joints  with  which  a  plumber  should  be  familiar  are 
very  numerous,  as  their  construction  must  necessarily  vary 
with  the  different  materials  of  which  the  pipes  are  formed, 
the  positions  in  which  pipes  are  placed,  and  the  purposes  for 
which  pipes  are  required. 

Joints  for  Lead  Pipes. — The  chief  joints  for  lead  pipes 
are :  (a)  Straight  and  branched  forms  of  plumbers'  joints ; 
(b)  Block  joints  ;  (c)  Flange  joints  ;  (d)  Lip  joints. 

Plumbers  should  be  capable  of  making  soldered  joints 
in  any  situation,  for  frequently  pipes  are  much  distorted  in 
getting  them  into  position  if  their  relative  positions  are  greatly 
altered  whilst  the  joints  are  made. 

All  young  plumbers  would  be  well  advised  to  avoid  the 
use  of  plumbing  irons  and  spirit-lamps,  etc.,  when  learning 
to  wipe  soldered  joints  on  the  smaller  sizes  of  pipes.  To 
manage  without  their  aid  a  plumber  must  be  quick  in  the 
manipulation  of  the  solder,  and  this  is  essential  in  order  to 
become  skilful  in  the  art  of  jointing.  Plumbing  irons, 
Swedish  torches,  and  spirit-lamps,  etc.,  are,  however,  very 
useful  appliances  when  used  in  their  proper  place. 

Preparation  of  Joints. — When  preparing  the  ends  of 
pipes  for  jointing,  this  part  of  the  work  should  be  neatly 
done.  The  faucet  end  for  an  underhand  joint  should  not 
be  opened  unduly  wide,  and  the  spigot  end  should  be 
slightly  opened  after  being  trimmed  in  order  that  no 
unnecessary  retardation  be  introduced  where  a  joint  is 
made.  Each  end  should  then  be  rasped  to  a  thin  edge,  and 
the  tarnish  or  smudge  applied.  After  the  shaving  is  done, 
the  prepared  ends  are  brought  together  and  made  secure, 
7 


98       DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

when  the  joint  is  ready  for  wiping.  Fig.  61  gives  three 
forms  of  plumbers'  joints,  those  at  A  and  B  being  shown 
partly  in  section  and  partly  in  elevation. 


FIG.  61. — Joints  for  lead  pipes. 

For  soil  and  waste  pipes  their  branches  should  curve  in 
the  direction  of  flow  as  at  C,  Fig.  61.    The  latter  form  of  joint 


PIPE   JOINTS  99 

requires  to  be  carefully  prepared,  or  the  solder  will  run 
through  into  the  pipes  during  wiping  ;  or  if  a  thick  edge  is  left 
either  at  the  front  or  at  the  side  of  the  joint  it  will  probably 
be  laid  bare  during  the  jointing  process. 

To  guard  against  solder  getting  into  pipes  it  is  a  good 
practice,  when  preparing  large  branch  joints,  to  smear  with 
plumbers'  black  the  inner  surfaces  of  the  opened  part,  and 
also  the  end  of  the  branch  piece  for  about  J  inch  on  both  its 
inner  and  outer  surfaces.  This  precaution  does  not  impair 
the  general  soundness  of  a  branch  joint,  and  no  trouble  will 
be  caused  by  solder  running  through,  provided  the  joint  is 
properly  prepared  and  is  not  played  with  too  long  when 
applying  the  solder. 

Another  precaution  when  preparing  the  spigot  end  to 
prevent  solder  running  through  the  joint  is,  first,  to  neatly 
fit  the  branch  piece,  when  a  mark  is  made  on  the  latter 
around  the  top  edge  of  the  opened  part.  The  branch  is  then 
removed,  and  a  groove  cut  with  a  saw  file  on  the  lower  side 
of  the  mark.  Afterwards  the  pipes  are  blacked  and  shaved, 
care  being  taken  not  to  shave  out  the  small  groove  in  the 
spigot  end.  When  the  prepared  branch  is  in  position,  the 
thin  edges  at  the  top  of  the  opening  may  be  driven  into  the 
groove  by  the  aid  of  a  small  hammer  and  blunt  iron  chisel. 

Openings  for  branches  should  stand  up  evenly  all  round. 
To  form  a  large  elliptical  opening  in  a  thin  lead  pipe,  a  hole 
may  be  bored  with  a  large  gimlet  or  other  suitable  tool  half 
an  inch  clear  of  each  end  of  the  major  axis.  A  slot  may 
then  be  formed  by  cutting  out  a  strip  of  lead  between  the 
gimlet  holes,  and  afterwards  opened  up  with  the  aid  of  a  heavy 
bent  pin  and  small  hand  dummy. 

Gauges. — To  prepare  joints  on  straight  pipes  of  uniform 
size  is  a  simple  matter,  as  the  ends  of  the  pipes  only  require 
fitting  together  in  order  that  the  length  of  the  shaving  can 
be  correctly  proportioned  on  each  end.  For  branch  joints 
gauges  are  necessary  where  uniformity  of  size  is  to  be 
maintained. 

Gauges  are  often  made  of  sheet  brass,  and  may  take 
the  form  given  in  Fig.  62.  It  is  an  advantage  to  have 
two  of  these  gauges,  one  for  small  and  the  other  for  large 


100     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

branch  joints.  Down  the  centre  of  the  gauge,  Fig.  62,  a 
number  of  small  holes  are  made  in  which  one  point  of  a  pair 
of  compasses  can  be  inserted  for  marking  off  the  portion  to 
be  shaved.  The  central  point  at  the  bottom  edge  is  useful 
when  making  right-angled  branch  joints,  as  it  can  readily 
be  fixed  over  the  centre  of  the  opening  so  as  to  make  the 
scribing  equal  on  each  side.  For  curved  branch  joints  the 
central  point  is  not  of  much  service,  as  the  gauge  requires  to 
be  fixed  a  little  off  the  centre  according  to  the  angle  at 
which  the  branch  joins  the  opened  pipe.  After  the  true 


FIG.  62. — Gauge  for  marking  branch  joints. 

position  of  the  gauge  has  been  obtained  the  scribing  for  the 
joint  is  done  from  each  side. 

Methods  of  Supporting  Joints. — The  methods  of  staying 
joints  for  wiping  purposes  are  very  varied,  and  are  largely 
governed  by  the  sizes  of  the  pipes,  by  the  positions  in  which 
the  joints  are  to  be  made,  by  the  packings  at  disposal,  and  by 
the  intelligence  of  the  individual  who  is  staying  them.  In 
new  buildings,  where  bricks  and  timber  are  plentiful,  these 
are  largely  used  for  fixings  on  floors  and  other  flat  surfaces  : 
where  joints  are  made  against  walls,  fixing  points  are  very 
useful  for  staying  purposes.  The  use  of  strong  cord  and 
fixing  points  will  in  many  cases  dispense  with  the  aid  of  more 
cumbersome  fixings. 


PIPE   JOINTS 


101 


When  staying  branch  joints  for  soil  and  waste  pipes,  more 
care  is  necessary  than  for  thicker  lead  pipes,  for  unless  the 
weight  of  the  branch  be  also»supported  there  may  be  danger 
of  the  whole  falling  down  when  getting  up  the  wiping  heat. 

An  old  but  excellent  method  of  supporting  branches  in 
large  lead  pipes  whilst  wiping  a  joint  is  illustrated  in  Fig.  63. 
After  the  opened  part  and  spigot  end  have  been  prepared,  two 
pieces  of  wood  about  a  foot  in  length  and  1J  inches  square 
are  placed  over  each  other  inside  the  pipe ;  upon  these  two 
wedge  pieces  are  fixed  back  to  back  in  order  to  keep  the  spigot 
end  from  protruding  too  far  into  the  opening.  These  packings, 


FIG.  63. — Method  of  supporting  pipe  whilst  jointing. 

of  course,  are  placed  in  position  before  the  branch  is  inserted. 
The  weight  of  the  branch  may  be  principally  supported  as 
at  S,  Fig.  63,  or  in  any  other  suitable  manner.  To  secure 
the  branch  a  piece  of  cord  may  be  passed  round  the  bend, 
with  the  ends  fastened  down  to  the  bench  on  opposite  sides 
of  the  branch.  Should  a  branch  be  a  long  one,  the  wood 
fixings  may  be  left  in  position  whilst  it  is  carried  from  the 
bench  and  fixed  in  its  place.  The  packings  inside  the  branch 
may  be  readily  displaced  by  either  a  piece  of  wood  or  a 
length  of  iron  tube.  In  the  case  of  vertical  pipes  the 
packings  may  be  displaced  by  a  plumb-bob,  but  access  will  be 
necessary  for  regaining  the  packings.  The  object  of  having 


102     DOMESTIC  SANITARY    ENGINEERING    AND    PLUMBING 

packings  for  the  inside  of  branch  joints  in  four  parts,  instead 
of  in  three  pieces,  is  to  allow  them  to  pass  more  readily 
round  a  bend.  • 

Many  methods  are  in  use  for  holding  brasswork  to  lead 
pipes  whilst  joints  are  made.  Several  forms  of  metal  clamps 
and  fixings  may  be  obtained  for  this  purpose,  and  some  are 
very  useful  appliances.  The  tail-pieces  of  unions  and  taps,  etc., 
are  not  difficult  to  stay,  however,  when  joining  them  to  lead 
pipes.  When  a  brass  tap  is  branched  into  a  lead  pipe,  one 
method  of  staying  the  former  whilst  a  joint  is  made  is  to 
file  a  groove  near  to  the  tail  end  and  to  drive  the  lead  into 
it  from  around  the  edge  of  the  opened  part.  A  second  method 
is  to  form  two  or  three  coarse  threads  with  small  stocks  and 
dies  on  the  tail  end  of  a  tap,  and  to  make  the  hole  in  the 
pipe  suitable  in  size  for  the  tap  to  be  screwed  into  it.  This 
makes  a  simple  and  substantial  fixing,  especially  if  the  lead 
round  the  edge  of  the  opening  is  worked  up  and  is  also  driven 
into  the  threads.  Another  method  for  holding  a  tap  whilst 
making  a  joint  is  to  fuse  or  "  burn  "  the  edges  of  the  lead  to 
the  brasswork  with  a  well-faced  soldering  bolt,  which  is  heated 
to  dull  redness.  The  lead  unites  with  the  tinning  on  the 
brasswork,  and  this  most  readily  occurs  when  the  brasswork 
is  well  heated  just,  prior  to  "  burning  on,"  as  it  is  termed. 
The  worst  feature  in  connection  with  this  method  is  the 
frequent  facing  of  '  the  soldering  bolt.  It,  however,  securely 
holds  the  brasswork  when  the  "  burning  "  is  properly  done, 
and  is  not  liable  to  give  way  if  the  joint  is  wiped  in  a 
reasonable  time.  To  "  burn  on "  it  is  important  that  the 
soldering  bolt  has  a  good  face,  otherwise  "  burning "  is 
indifferently  done. 

For  fixing  brass  tail-pieces  on  the  ends  of  pipes  "  burning 
on  "  is  often  very  convenient,  especially  for  the  smaller  sizes 
of  fittings.  If  well  done,  "  burning  on  "  resembles  a  narrow 
copper-bolt  joint,  excepting  that  neither  strip  of  lead  nor 
solder  is  used.  Resin,  however,  is  used  as  a  flux. 

Another  convenient  method  for  supporting  tail-pieces  is 
by  using  a  number  of  narrow  wood  strips.  These  can  be 
pushed  through  the  tail-pieces  into  the  pipe,  and  a  reliable 
and  simple  fixing  often  obtained. 


PIPE   JOINTS 


103 


When  wiping  joints  some  discretion  requires  to  be 
exercised  with  regard  to  the  solder  used  ;  it  is  clearly  obvious 
that  for  soil  and  waste  pipes  the  joints  should  be  lightly 
wiped,  when  compared  with  those  for  water  pipes,  which  are 
required  to  withstand  more  or  less  considerable  pressure. 

Many  plumbers  experience  difficulty  in  making  a  good 
shaped  light  joint  of  moderate  length,  although  they  have  no 
apparent  difficulty  in  making  a  heavy  joint.  As  a  rule,  the 
reason  why  many  are  unable  to  wipe  light  joints  is  owing  to 
the  use  of  thin,  flabby  cloths. 


Block  joint. 


Lip  joint. 
FIG.  64. 


Flange  joint. 


To  wipe  light  joints  of  moderate  length  a  fairly  stiff 
cloth  is  essential,  and  many  good  joint  makers,  in  order  to 
impart  the  necessary  stiffness,  insert  a  thin  piece  of  zinc  in 
the  centre  of  their  cloths.  Others  introduce  a  thin  layer  of 
cardboard  for  the  same  purpose.  These  stiffened  cloths  are 
used  chiefly  for  shaping  the  larger  sizes  of  joints,  more  pliable 
ones  being  used  for  getting  up  the  heat. 

Block  Joint. — For  lead  soil  pipes  which  are  fixed  in 
recesses  inside  buildings  the  block  joint  is  very  suitable, 
as  it  forms  both  a  joint  and  a  good  fixing  for  the  pipe.  The 
upper  edge  of  the  hole  in  the  wood  block  should  be  well 


104     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

rounded  off  as  in  A,  Fig.  64.  A  lead  collar  is  placed 
directly  upon  the  wood  support,  and  the  faucet  end  before 
being  opened  should  be  cut  to  stand  not  more  than  f  inch 
clear  of  the  top  of  the  support.  When  the  end  is  opened 
with  the  tanpin,  a  space  should  be  left  between  the  lip  and 
lead  collar  so  as  to  allow  the  solder  to  now  under  the  lip. 
The  lead  collar  would,  of  course,  be  shaped,  and  most  of  the 
preparation  for  soldering  done,  before  a  length  of  pipe  is 
placed  in  position. 

Flange  Joint. — At  B,  Fig.  64,  a  flange  joint  is  shown; 
this  is  inferior  to  the  block  joint,  although  it  is  made  very 
much  in  the  same  manner.  In  the  flange  joint  the  sharp 
aris  only  is  taken  off  the  woodwork,  a  lead  collar  being  used 
as  before,  with  the  faucet  end  flanged  over  on  to  the  collar. 


FIG.  65. — Method  of  jointing  tin-lined  lead  pipe. 

Lip  Joint. — The  lip  joint  C,  Fig.  64,  is  more  suitable  for 
gas  pipes  than  for  either  water-pipe  or  waste-pipe  work.  In 
certain  districts  where  inferior  work  is  done  the  lip  joint  is 
often  vised,  on  account  of  its  cheapness,  for  joining  brass 
connections  to  overflow  pipes,  to  lead  traps,  and  to  hot-water 
service  pipes,  etc. 

There  are  certain  times,  however,  when  a  wiped  joint  is 
no  stronger  than  a  lip  joint ;  in  fact  the  latter  may  be  much 
the  stronger  of  the  two.  This  may  happen  with  a  very  short 
brass  tail-piece  when  joined  to  a  lead  pipe  with  an  underhand 
joint.  Under  such  conditions  the  joint  is  principally  formed 
on  the  pipe,  with  the  result  that  the  end  of  the  pipe,  which 
has  been  reduced  in  substance,  is  nearly  laid  bare. 

Joints  for  Tin-Lined  Lead  Pipes. — When  solder  is  used, 
the  joints  for  these  pipes  are  not  prepared  in  the  same 
manner  as  those  for  lead  pipes,  as  the  heat  of  the  solder 


PIPE   JOINTS 


105 


would  melt  the  tin  linings  in  the  neighbourhood  of  the  joints, 
lay  bare  the  lead  to  the  action  of  the  water,  and  the  latter 
in  its  passage  through  the  pipes  may  be  considerably  retarded. 
To  avoid  destroying  the  tin  linings  thin  brass  ferrules 
are  sometimes  used,  as  in  Fig.  65.  The  ends  of  the 
pipes  may  be  slightly  expanded  by  means  of  a  steel  pin 
specially  made  for  the  purpose,  and  the  ferrule  when  inserted 
should  be  tight  fitting ;  the  joint  is  then  wiped  with  plumbers' 
solder  in  the  usual  way.  During  the  process  of  wiping  there 
is  still  the  liability  of  destroying  a  little  of  the  lining  beyond 
the  ends  of  the  ferrule,  although  this  may  be  avoided  to  a 


FIG.  66. — Branch  joint  for  tin-lined  lead  pipe. 

certain  extent  by  the  use  of  longer  ferrules  than  that  shown 
in  Fig.  65. 

A  method  of  preparing  a  branch  joint  for  tin-lined  lead 
pipes  is  indicated  in  Fig.  66.  It  is,  however,  troublesome 
to  prepare,  and  it  is  necessary  to  cut  in  two  the  pipe  into 
which  the  branch  is  to  be  made  and  to  mitre  the  ends 
as  shown.  Each  of  the  three  ends  may  be  slightly  expanded 
as  before  described,  and  when  blacked  and  shaved,  a  brass 
tee  piece  requires  to  be  inserted,  and  a  joint  wiped  over  the 
ends,  so  as  to  form  a  combined  branch  and  underhand  joint. 
The  dotted  lines  in  Fig.  66  represent  the  brass  tee  piece. 

Another  method  of  joining  tin-lined  lead  pipes  is 
illustrated  in  Figs.  67  and  68.  In  Fig.  67  a  simple  form  of 
union  coupling  is  shown,  and  the  ends  of  the  pipes  are  simply 


106     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

flanged  over  and  brought  together  by  means  of  the  screwed 
cap  and  ferrule.  Fig.  68  gives  a  special  gun-metal  fitting, 
the  ends  of  the  pipes  being  flanged  and  treated  in  a  similar 
manner  to  that  shown  in  Fig.  67. 


WASHER 


FIG.  67. — Joint  for  tin-lined  lead  pipes. 

The  latter  is  the  better  method  of  joining  tin -lined  lead 
pipes,  but  the  special  fittings  make  such  pipes  expensive. 

Burnt  Joints  for  Lead  Pipes. — Where  lead  pipes  are  used 
for  conveying  acids,  burnt  joints  require  to  be  made,  as 
ordinary  soldered  joints  are  more  or  less  rapidly  destroyed. 


FIG.  68.— Branch  joint  for  tin-lined  lead  pipes. 

Burnt  joints  are  used  to  a  limited  extent  for  botli  lead  soil 
and  waste  pipes,  and  several  forms  of  burnt  joints  for  such 
pipes  are  given  in  Fig.  69.  At  A  an  ordinary  form  of  lip 
joint  is  shown,  and  the  only  difference  between  it  and  a 
soldered  one  is  that  a  strip  of  lead  is  used  in  lieu  of  solder 
when  making  the  joint.  Where  a  horizontal  pipe  may  be 


PIPE    JOINTS 


107 


turned  the  joint  B,  Fig.  69,  can  be  adopted.  C  and  D  give 
two  different  branch  joints ;  the  one  at  C  may  be  made  when 
the  branch  piece  is  in  the  position  shown.  D  is  a  much 


FIG.  69. — Forms  of  burnt  joints. 

stronger  type  of  joint,  but  to  make  it  the  whole  branch  must 
be  free,  so  that  it  can  be  turned  on  either  side  whilst  the 
lead  is  built  up  upon  the  joint. 


108     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

With  regard  to  the  merits  and  demerits  of  burnt  joints 
for  pipes  in  general  work,  the  latter  far  outweigh  the  former. 

The  chief  disadvantages  of  burnt  joints  for  lead  pipes 
are :  the  time  occupied  in  making  the  joints ;  the  limited 
positions  in  which  they  can  be  made ;  and  the  amount  of 
space  necessary,  as  every  part  of  the  joint  must  be  readily 
accessible  when  being  made. 

Joints  for  Copper  Pipes. — The  usual  method  of  jointing 
copper  pipes,  which  are  used  either  for  hot-water  services  or 
for  heating  apparatus,  is  by  means  of  screwed  socketed  joints. 
The  coarse  or  ordinary  gas  tube  thread  is  frequently  used, 
and  the  pipes  require  to  be  thick  enough  so  as  not  to  be 
unduly  weakened  when  the  threads  are  cut.  Brass  or 
gun-metal  fittings  are  used,  and  after  the  joints  have  been 
tightly  screwed  up,  the  fittings  and  pipes  are  sweated 
together  with  fine  solder.  This  mode  of  jointing  necessitates 
the  free  use  of  union  connections  in  order  that  all  the  ends 
of  the  fittings  may  be  soldered  to  the  pipes. 

Screwed  joints  for  light  copper  pipes,  which  only  permit 
of  fine  threads  being  cut,  are  not  suitable  for  either  hot-water 
services  or  for  heating  apparatus.  Such  joints  are  not 
durable  as  a  rule,  chiefly  owing  to  galvanic  action,  which 
corrodes  the  soldered  joints  and  causes  the  latter  to  leak. 

It  may  be  asked  that  if  screwed  and  soldered  joints  on 
.light  copper  pipes  are  liable  to  fail  through  galvanic  action, 
why  are  not  those  in  the  first  case,  where  stronger  joints  are 
made  and  soldered  ?  The  reason  is  not  far  to  seek.  With 
comparatively  strong  pipes  and  fittings,  the  joints  can  be 
made  water-tight  without  the  use  of  solder,  the  latter  serving 
more  or  less  as  a  mere  safeguard  against  leakage.  With  thin 
copper  pipes  and  screwed  sockets,  even  assuming  the  joints  at 
the  outset  did  not  depend  for  their  water-tightness  upon  the 
soldering,  it  is  scarcely  to  be  expected  that  they  will  remain 
long  in  that  condition,  owing  to  the  varying  strains  to  which 
the  joints  are  subjected  by  fluctuations  of  temperature.  As 
soon  as  a  certain  class  of  water  finds  its  way  between  the 
threads  of  the  pipes  and  those  of  the  fittings,  and  comes  in 
contact  with  the  solder,  the  latter  is  slowly  destroyed,  owing 
to  a  galvanic  couple  being  formed. 


PIPE   JOINTS 


109 


Stronger  joints  on  copper  pipes,  when  soldered,  may  be 
liable  to  fail  through  galvanic  action  provided  they  were  im- 
perfectly made,  or  depended  for  their  soundness  upon  the 
soldering. 

Copper  tubes  of  steam  pipe  strength  do  not  require 
soldering  at  the  joints,  but  such  tubes  are  too  expensive  for 
low  pressure  work. 

Light  copper  tubes,  however,  may  be  safely  employed  for 
hot-water  services  and  similar  uses,  provided  suitable  joints 
are  adopted.  The  failure  of  thin  copper  pipes,  as  already 
explained,  is  due  to  the  weakness  of  the  joints  and  not  to  the 
thinness  of  the  tubes  themselves. 

Compression-Joints. — The  most   suitable   joints    for   thin 


FIG.  70. — Leighs'  compression  joint  for  light  copper  pipes. 

copper  tubes  are  those  where  their  ends  are  brought  together 
and  made  air  and  water-tight  by  compression.  Compression- 
joints  have  been  used  by  heating  engineers  on  the  Continent 
of  Europe  for  some  years,  and  more  recently  a  good  form  of 
compression-joint  has  been  patented  by  Leighs  of  Manchester. 
The  construction  of  the  latter  joint  is  clearly  shown  in  Fig.  70. 
The  ends  of  the  pipes  to  be  joined  are  prepared  by  expanding 
one  end,  whilst  the  other  has  a  beaded  shoulder  formed  in  it. 
By  means  of  a  screwed  cap  and  sleeve  piece  one  end  is  forced 
inside  the  other,  and  a  substantial  joint  is  formed  where  no 
jointing  material  is  required,  the  soundness  of  the  joint  relying 
upon  the  closeness  of  the  metal  surfaces.  A  washer  W  is 
placed  behind  the  raised  bead  to  prevent  the  latter  being  cut 
or  chafed  when  screwing  up  the  joint. 


110     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

For  preparing  the  pipe  ends  two  machines  are  necessary, 
one  for  making  the  bead  and  the  other  for  expanding  the 
ends.  Special  fittings  are  also  required,  such  as  tees,  elbows, 
etc. :  these  have  their  ends  coned  in  order  to  receive  the 
tubes  upon  which  the  beaded  shoulders  are  formed.  With 
regard  to  the  soundness  and  strength  of  the  compression-joint 
shown,  it  is  stated  by  the  Patentees  that  a  1^-inch  seamless 
copper  tube  of  20  I.W.G.,  when  connected  with  various 
fittings,  proved  tight  with  an  internal  pressure  of  700  Ib. 
per  sq.  inch,  and  that  a  tensile  force  of  8J  tons  was 
necessary  to  pull  a  joint  apart. 

Iron  Pipe  Joints. — Wrought-iron  pipes  are  usually  joined 
with  screwed  socketed  joints,  whilst  cast  -  iron  pipes  are 

LEATHER. 
WASHER, 


FIG.  71. — Left  and  right  screwed  joint  for  "  Health  "  water  pipe. 

generally  jointed  either  by  flanges  which  are  screwed  together 
with  iron  bolts  or  by  a  spigot  and  socket  form  of  joint. 

The  method  of  making  the  joints,  and  the  jointing 
materials  employed,  depend  chiefly  upon  the  purpose  for 
which  the  pipes  are  required.  For  screwed  joints  on  wrought- 
iron  pipes  a  mixture  of  red  and  white  lead  mixed  to  the 
consistency  of  thick  paint  is  frequently  used.  It  is  usually 
necessary,  however,  in  the  case  of  pipes  which  convey  water, 
air,  or  steam  under  pressure,  to  wrap  fine  hemp  between  the 
threads  on  the  ends  of  the  pipes  after  painting  them.  Pipe- 
joint  compounds  may  also  be  obtained  for  making  screwed 
joints  air  and  water  tight,  and  these  preparations  are  usually 
superior  to  mixtures  of  red  and  white  lead. 

Fig.  7 1  shows  a  screwed  joint  for  the  "  Health  "  water  pipe, 
which  consists  of  a  wrought  iron  tube  with  a  tin  lining.  In 
the  centre  of  each  socket  a  space  is  provided  in  which  a 


PIPE   JOINTS  111 

leather  washer  is  loosely  placed.  Each  joint  is  made  with 
right  and  left-hand  threads,  so  that  each  socket  forms  a  union 
coupling.  When  the  pipe  ends  are  prepared  the  tin  lining 
is  left  a  little  longer  than  the  iron  tube,  and  is  afterwards 
flanged  over  the  ends.  No  other  jointing  material  is  required, 
for  when  a  socket  is  screwed  up  the  ends  of  the  pipes  are 
brought  to  press  evenly  against  the  leather  washer. 

Special  fittings  are  necessary  in  connection  with  the 
"  health "  water  pipe,  and  these  are  supplied  by  the  manu- 
facturers of  the  pipe. 

The  joint  used  in  connection  with  high  pressure  heating 
apparatus  is  illustrated  in  .Fig.  72.  This  is  also  a  left  and 
right  screwed  joint,  but  the  pitch  of  the  threads  is  less  than 
that  of  the  "  health "  water  pipe.  The  sockets  are  very 


•*•.  _  .   v 

FIG.  72. — Left  and  right  screwed  joint  for  small  bore  heating  apparatus 


strong,  and  cavities  are  provided  at  their  centres  where  the 
pipe  ends  meet.  Special  screwing  tackle  is  necessary  for 
high  pressure  joints,  as  one  pipe  end  is  coned  to  form  a  chisel 
edge,  whilst  the  other  is  prepared  with  a  true  flat  surface. 
The  ends  are  brought  together  with  the  aid  of  powerful  pipe 
wrenches,  so  that  the  sharp  edge  of  the  one  cuts  into  the  flat 
face  of  the  other.  No  jointing  material  of  any  description  is 
used,  metallic  contact  being  responsible  for  the  soundness  of 
the  joint. 

For  cast-iron  pipes  the  spigot  and  socket  class  of  joint  is 
the  most  common.  In  Fig.  73  the  general  form  of  joint  for 
iron  waste,  soil,  and  drain  pipes  is  shown.  Several  strands  of 
tarred-yarn  are  first  inserted  in  the  socket,  and  the  upper 
1 1  inches  of  depth  run  full  of  molten  lead. 

To  run  joints  properly  when  in  horizontal  situations,  clay 


112     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

bands  or  their  equivalent  are  essential.  The  bands  are  placed 
around  the  sockets  to  prevent  the  lead  escaping  when  running 
the  joints ;  after  the  joints  are  run,  the  cooling  lead  contracts 
and  leaves  a  small  space  between  it  and  the  surfaces  of  the 
pipes.  After  going  once  round  a  joint  with  a  chisel  and 
hammer,  to  free  the  edge  of  the  lead  from  the  surface  of  the 
pipe,  the  joint  is  made  sound  by  well  caulking  it. 

Frequently  the  joints  on  soil  pipes  are  indifferently  made, 
owing  to  the  rope-yarn  being  insufficiently  staved.  The 
result  of  this  is  that  the  metallic  lead  is  driven  into  the 
sockets  instead  of  being  finished  flush  with  their  top  edges. 

"  Lead  Wool." — Instead  of  making  joints  in  connection 
with  iron  soil  and  drain  pipes  with  molten  lead,  "  lead  wool " 
may  often  be  utilised  with  advantage.  This  material  takes 


FIG.  73. — Spigot  and  socket  joint  for  cast-iron  pipes. 

the  form  of  thin  threads  of  metallic  lead,  which  are  formed 
into  strands  for  inserting  into  the  sockets  of  pipes.  The 
joints  are  partly  made  in  the  usual  way  by  first  intro- 
ducing tarred-yarn,  the  "  lead  wool "  being  used  for  the  upper 
inch  of  the  joint,  and  both  the  yarn  and  lead  should  be  well 
staved  when  inserted  into  the  sockets.  Very  substantial 
joints  can  be  made  with  "  lead  wool,"  for  when  properly 
caulked  it  forms  a  compact  mass  of  lead,  completely  filling 
every  space  in  the  depth  to  which  it  is  inserted. 

Lead  is  not  a  suitable  jointing  material  for  iron  waste 
pipes  which  discharge  very  hot  water,  owing  to  the  unequal 
expansion  and  contraction  of  iron  and  lead.  For  such  pipes 
iron  borings  should  be  used  in  lieu  of  lead,  and  rust  joints 
made. 

Must  joints  are  only  suggested  for  the  discharge  of  very 


PIPE    JOINTS 


113 


hot  liquids,  and  not  for  general  use  for  waste  pipes,  as  lead  is 
a  suitable  jointing  material  for  the  majority  of  cases. 

Expansion  Joints  for  Waste  Pipes. — Where  rust  joints' are 
deemed  desirable  for  cast-iron  waste  pipes,  provision  must  be 
made  for  expansion  and  contraction  of  the  pipes  on  account 
of  the  rigidity  of  these  joints. 

Bends  in  pipes  allow  a  certain  amount  of  movement  to 
take  place,  and  a  few  bends  in  a  stack  of  pipes  may  permit 
of  all  the  movement  required.  Where,  however,  a  long 
stretch  of  waste  pipes  is  rigidly  fixed  between  two  given 
points,  and  subjected  to  extremes  of  temperature,  an  expan- 
sion joint  similar  to  Fig.  74  may  be  necessary  to  allow  a 
little  movement  to  take  place.  The  construction  of  the 


FIG.  74.— Expansion  joint  for  cast-iron  pipes. 

joint  is  clearly  shown,  the  packing  material  in  the  gland 
being  asbestos  or  other  suitable  material. 

The  joints  for  iron  water  mains  are  much  stronger  than 
those  for  drains  and  soil  pipes,  as  the  former  require  to 
withstand  more  or  less  considerable  internal  pressure,  and 
the  sockets  of  water  mains  are  also  subjected  to  greater 
strain  by  the  extra  caulking  they  receive. 

Joints  in  water  mains  are  made  by  first  inserting  ordinary 
spun-yarn,  as  tarred-yarn  is  liable  to  taint  the  water  for  a 
considerable  time.  The  remaining  space  in  the  socket  is  then 
filled  either  with  molten  lead  or  with  "  lead  wool."  The  depth 
of  lead  required  varies  with  the  size  of  the  pipes,  with  the 
form  in  which  the  lead  is  used,  and  with  the  character  of  the 
ground  through  which  the  pipes  are  laid. 


114     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

For  water  mains  of  3  inches  to  6  inches  diameter,  if  the 
joints  are  run  in  the  ordinary  manner,  the  minimum  depth  of 
lead  for  the  smaller  size  should  be  2  inches,  and  2J  inches 
deep  for  the  larger  size.  If  "  lead  wool  "  is  used  the  depth 
of  lead  may  be  J-  inch  less  in  each  case.  The  reason  why 
less  "  lead  wool "  may  be  used  than  molten  lead  for  making 
joints  is  due  to  the  fact  that  the  former  can  be  firmly  caulked 
for  the  whole  of  its  depth,  whilst  the  latter  is  chiefly  affected 
by  caulking  for  a  limited  depth. 

Turned  and  lored  joints,  Fig.  75,  possess  the  advantages 
of  dispensing  with  the  use  of  yarn,  which  is  subject  to  decay, 
and  of  permitting  air-tight  joints  to  be  made  by  smearing 
the  prepared  ends  with  tallow  or  similar  substance.  In  the 


FIG.  75. — Turned  and  bored  joint  for  cast-iron  pipes. 

case  of  pipes  which  carry  little  pressure,  and  where  turned 
and  bored  joints  are  used,  the  angular  space  may  be  filled 
with  portland  cement  or  by  a  bituminous  composition  in  lieu 
of  metallic  lead. 

The  chief  drawback  of  turned  and  bored  joints  is  their 
rigidity,  but  this,  however,  can  be  largely  overcome  by 
introducing  in  a  line  of  pipes  at  regular  intervals  an  ordinary 
spigot  and  socket  joint.  Where  pipes  with  turned  and  bored 
joints  convey  liquids  under  pressure,  metallic  lead  should  be 
used  as  the  jointing  material. 

Spigot  and  socket  joints  for  hot-water  pipes  may  be  made 
in  different  ways.  A  common  method  of  making  a  joint  is 
to  partly  fill  the  annular  space  between  the  spigot  and  socket 
with  tarred  yarn,  and  to  fill  the  remaining  space  with  rust 
cement.  Another  method  is  to  first  insert  a  few  rings  of  spun 


PIPE   JOINTS 


115 


yarn  into  which  a  suitable  mixture  of  red  and  white  lead  has 
been  worked  ;  several  rings  of  tarred  yarn  are  afterwards 
inserted,  and  the  remaining  £  inch  to  1  inch  of  space  filled 
with  rust  cement.  A  third  method  is  to  first  insert  a  couple 
of  rings  of  tarred  yarn,  and  to  fill  the  remaining  space  with 
a  mixture  of  red  and  white  lead,  linseed  oil,  chopped  hemp, 
and  gold  size. 

Packing  rings  for  flange  joints,  Fig.  76,  largely  consist  of 
indiarubber,  asbestos,  metallic  lead,  and  corrugated  metal 
rings.  Indiarubber  rings  are  not  suitable  for  steam  pipes, 
but  are  better  suited  for  fixing  between  the  flanges  of  cold- 
water  pipes  and  fittings.  Eubber  is  also  fairly  durable  in 
contact  with  hot  water  which  does  not  exceed  180°  F.,  but 
when  the  temperature 
approaches  212°  F., 
and  over,  rubber  gets 
hard  and  readily 
cracks. 

Asbestos  rings 
make  good  packings 
where  flange  joints 
are  subjected  to 
moderately  high  tem- 
peratures. 

Where      metallic 

lead  rings  are  used  for  flange  joints,  the  flanges  require  to  be 
truly  and  smoothly  faced  in  order  to  prevent  leakage.  Lead 
rings  are  very  convenient  for  joints  which  are  periodically 
taken  apart,  as  they  can  be  re-used  after  smearing  them  over 
with  grease  or  oil. 

Corrugated  metal  rings  make  good  jointing  material  for 
flange  joints  on  high  pressure  steam  pipes  and  fittings.  The 
corrugations  form  a  series  of  concentric  rings,  and  after  the 
metal  rings  have  been  painted  and  covered  with  red  and 
white  lead  they  are  placed  between  the  painted  flanges, 
and  the  whole  securely  bolted  together.  A  little  fine 
hemp  may  be  added  to  the  cementing  material  so  as  to 
bind  it  together.  These  metallic  rings  are  usually  of  brass, 
and  by  squeezing  the  cementing  material  which  is  confined 


FIG.  76. — Flange  joint  for  iron  pipes. 


116      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

in  the    corrugations    against  the  flanges  a  substantial  joint 
is  made. 

Expansion  Joints  and  Bends. — Movement  is  provided  for 
in  hot-water  and  steam  pipes  by  means  of  expansion  joints 
and  bends.  The  expansion  joint  A,  Fig.  77,  is  made  of  brass 
or  gun-metal,  and  is  intended  for  use  in  connection  with  pipes 
with  screwed  joints.  It  consists  principally  of  a  sleeve  piece 
which  slides  through  a  stuffing  box  in  a  long  socket.  Ex- 
pansion joints,  however,  are  liable  to  leakage,  and  for  this 
reason  copper  expansion  bends  are  preferable  for  allowing 


FIG.  77. — Expansion  joint  and  expansion  bends. 

movement  in  pipes.  When  expansion  joints  are  used,  suffi- 
cient space  should  be  left  between  the  socket  of  the  sleeve 
piece  and  the  stuffing-box  to  enable  the  latter  to  be  repacked 
when  necessary.  If  fixed  as  shown  at  A,  there  might  be 
difficulty  in  removing  the  cap  and  gland  to  admit  of  new 
packing  material  being  added. 

Expansion  bends  may  take  different  forms  according  to 
the  positions  of  pipes.  B  and  C,  Fig.  77,  give  two  common 
forms  of  expansion  bends.  That  at  C  will  withstand  greater 
strains  without  distortion  or  fracture  than  that  at  B,  but  its 
outlet  and  inlet  ends  are  on  different  planes.  Both  ends  of 


PIPE   JOINTS  117 

bend  B  are  in  the  same  plane,  and  this  form  is  generally 
adopted  for  horizontal  pipes  which  have  a  limited  pitch. 

Wrought-iron  expansion  bends  are  not  so  suitable  as 
copper  ones  for  allowing  movement  in  pipes,  as  the  former 
are  too  rigid,  and  allow  the  strain  to  be  chiefly  concentrated 
on  the  screwed  joints. 

When  expansion  bends  are  essential  on  vertical  pipes, 
they  may  be  bent  in  spiral  form. 

Jones'  expansion  joint  is  largely  used  for  hot-water 
apparatus  in  horticultural  buildings,  and  it  is  also  suitable  for 
other  places  where  the  head  of  water  upon  the  pipes  does  not 
exceed  20  feet.  This  joint  is  for  pipes  with  plain  ends,  and 
consists  of  two  loose  collars,  two  rubber  rings  and  an  iron 

/&RASS  SOCKET 


FIG.  78. — Connection  between  outgo  of  w.c.  and  lead  branch. 

band,  along  with  two  bolts  and  nuts.  The  joint  is  made 
water-tight  by  compressing  the  rubber  washers,  with  the  aid 
of  the  bolts,  between  the  edges  of  the  loose  collar  and  those 
of  the  iron  bands. 

Joints  for  W.C.'s,  etc. — There  are  several  forms  of 
patented  joints  for  making  connections  between  the  outlets 
of  w.c.'s  and  lead  soil  pipe  branches,  but  one  of  the  most 
common  joints  is  that  shown  in  Fig.  78.  To  the  end  of  the 
lead  branch  pipe  a  brass  socket  is  soldered,  which  permits 
of  a  good  joint  being  made  with  the  earthenware  out-go  of 
a  w.c.  The  brass  socket  should  be  slipped  over  the  end 
of  the  pipe,  and  the  latter  turned  over  the  inside  shoulder 
of  the  socket,  and  be  finished  off  as  at  x,  Fig.  78.  Either 
portland  cement  or  an  elastic  cement  may  be  used  as 


118      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

jointing  material  for  the  socket,  after  a  ring  of  yarn  has 
been  inserted.  The  latter  is  the  better  jointing  material  of 
the  two. 

Where  w.c/s  are  provided  with  lead  traps,  or  where 
short  pieces  of  lead  pipe  are  soldered  to  their  outlets,  they 
can  be  soldered  directly  to  the  lead  branches. 

To  enable  a  sound  joint  to  be  made  between  a  lead  and 
an  iron  pipe,  a  brass  sleeve  piece  or  ferrule  is  first  passed 
over  the  end  of  the  lead  pipes,  and  soldered  to  it  as 
in  Fig.  79.  The  purpose  of  the  ferrule  is  to  protect 
the  lead,  and  to  impart  sufficient  rigidity  to  enable  a 
caulked  joint  to  be  made. 


LEAD  6RAWCH 

t 


FIG.  79. — Connection  between  lead  branch  and  iron  junction. 

When  joining  a  lead  soil  pipe  with  an  earthenware 
drain,  it  is  better,  on  account  of  the  width  of  the  earthen- 
ware socket,  to  allow  the  lead  pipe  to  protrude  about  half  an 
inch  or  so  into  the  bend  below  the  edge  of  the  ferrule,  as 
at  S,  Fig.  80.  This  keeps  the  lead  pipe  in  its  place  and 
simplifies  the  making  of  the  joint. 

Joints  for  Earthenware  Drain  Pipes. — The  common  form 
of  joint  for  earthenware  pipes  is  not  one  which  admits  of 
being  readily  made  in  a  satisfactory  manner.  The  chief 
difficulties  in  connection  with  it  are :  Maintaining  a  true 
alignment  at  the  invert  of  the  pipes,  and  in  keeping  the 
inside  of  the  pipes  smooth,  and  free  from  protruding  matter 


PIPE   JOINTS 


119 


at  the  joints.     Portland  cement,  either  neat  or  mixed  with 
sand,  is  the  usual  jointing  material. 

In  Fig.  81  a  couple  of  strands  of  rope-yarn,  which  have 
first  been  steeped  in  liquid  cement,  are  pressed  firmly  into 
the  socket,  the  remaining  space  being  filled  with  cement  and 
trowelled  off  as  shown. 

The  chief  draw- 
backs associated  with 
yarn  are,  it  is  subject 
to  decay,  and  to  leave 
cavities  in  the  sockets 
where  organic  matter 
may  gather,  and  unless 
yarn  is  carefully  used  it 
is  liable  to  pass  through 
the  joints  and  cause 
stoppages  in  pipes. 

Where  solid  cement 
joints  are  made,  some 
form  of  scraper  or  dis- 
placer  is  essential  to 
remove  the  surplus 
cement  which  passes 
into  the  pipes  during 
the  making  of  the 
joints.  The  removal  of 
cement  from  the  inside 
of  pipes  often  results 
in  roughening  their  sur- 
faces, and  in  impairing 


FIG.  80. — Method  of  connecting  lead  soil- 
pipe  with  a  drain. 


the  general  efficiency  of 
the  drain.  As  any  sur- 
plus cement  must  be 

removed  immediately  after  a  joint  is  made,  and  whilst  it 
is  still  soft,  the  tendency  is  for  the  cement  to  run  a 
little  and  to  form  a  small  ridge  along  the  invert  at  each 
joint ;  there  is  also  difficulty  in  obtaining  a  true  invert,  and 
frequently  the  joints  form  a  series  of  steps  unless  something 
is  done  to  prevent  it. 


120     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


Patent  Joints. — To  overcome  the  drawbacks  which 
accompany  the  use  of  ordinary  spigot  and  socket  joints, 
patented  joints  from  time  to  time  have  been  introduced. 
These  joints  possess  the  advantage  of  allowing  the  pipes  to 
be  easily  laid,  true  alignments  of  inverts  to  be  obtained,  and 

many  patent  joints  can 
be  made  in  water-logged 
ground  without  in  any 
way  affecting  the  joint- 
ing material.  The  chief 
disadvantage  of  pipes 
with  patent  joints  is 

FIG.  81. — Common  form  of  spigot  and  .  .    V  .  , 

socket  joint  for  earthenware  drains.  their  higher  initial  COSt. 

In  Hassall's  patent 

joint,  Fig.  82,  bituminous  rings  are  cast  both  at  the  front 
and  back  of  the  socket ;  other  rings  are  also  cast  to  coincide 
with  these  on  the  spigot  end  of  the  pipes,  and  the  space 
between  the  rings  is  filled  with  cement  in  a  semi-liquid 
state.  The  joint  shown  in  Fig.  82  is  known  as  a  double 
lined  one,  the  rings  at  x  being  omitted  in  the  single  lined 
form.  Single  lined  joints  admit  of  the  use  of  cement  in 
the  plastic  state,  but  when  it  is  desirable  to  use  liquid 
cement  clay  bands  are  necessary  round  the  sockets.  Other 
forms  of  patent 
joints  are  made  in 
which  composition 
rings  are  not  used, 
and  where  true  in- 
verts are  obtained 
by  means  of  studs 
in  the  sockets.  In 
other  cases  special 

forms  of  construction  are  introduced  at  both  the  spigot  and 
at  the  socket  ends  of  pipes.  One  of  the  latter  type  is  known 
as  the  "Yarrow"  joint,  and  is  illustrated  in  Fig.  83.  To 
prevent  the  cementing  material  escaping  from  the  cavity 
when  the  joint  is  being  run,  a  little  plastic  clay  is  used  at 
both  the  front  and  back  of  the  joint,  as  in  Fig.  83. 

In  Ames   and    Crosta's  joint,  Fig.    84,  a   little   clay   or 


FIG.  82. — HassaH's  patent  joint. 


PIPE   JOINTS 


121 


cement  is  used  at  the  front  and  back  of  the  sockets  when 
running  in  the  cement,  but  the  true  alignment  of  the 
invert  is  preserved  by  studs  which  are  formed  in  the  bottom 
of  the  socket. 

Another  form  of  patent  joint,  Fig.   85,  differs  again  from 


CLAV 


FIG.  83. — The  Yarrow  joint. 

those  already  shown.  In  this  case  the  inside  of  the  socket  is 
made  sloping,  in  order  that  the  spigot  end,  when  in  position, 
will  be  raised  to  form  a  true  invert.  For  this  joint  the 
cement  is  intended  to  be  used  in  the  plastic  state,  and  the 
principal  feature  of  the  joint  appears  to  be  the  provision 
made  for  centering  it. 


Ci-Af    OR    OTHER 

PLAS-nc     MATERIAL 


FIG.  84. — Ames  and  Crosta's  joint. 

When  jointing  earthenware  pipes,  special  care  is  essential 
in  the  selection  of  the  jointing  material  if  they  are  to  remain 
sound  for  any  length  of  time. 

The  use  of  portland  cement  as  a  jointing  material  for 
earthenware  pipes  has  been  responsible  for  many  failures  on 
account  of  the  cement  expanding  and  bursting  the  sockets. 


122     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


This  is  a  trouble  difficult  to  avoid  in  ordinary  practice,  for 
seldom  is  portland  cement  tested  as  regards  its  suitability, 
except  in  large  works,  where  a  competent  clerk  of  works 
is  employed.  So  far  as  earthenware  drains  are  concerned, 
even  assuming  that  reliable  portland  cement  is  used  for  the 
joints,  the  latter  are  too  rigid,  as  any  slight  unevenness  in 
the  settlement  of  the  ground  results  in  joints  or  pipes  being 
fractured. 

The  easy  manner  in  which  earthenware  pipes  are 
damaged  has  been  responsible  for  the  introduction  of  iron 
pipes  where  reliable  drains  are  required. 

Elastic  Cement. — The  difficulty  associated  with  earthen- 
ware pipes  can,  however,  be  overcome  to  a  great  extent  by 
using  a  jointing  material  of  a  slightly  yielding  nature. 
Various  materials,  such  as  resin,  tallow,  bituminous  substances, 

sand,  chalk,  etc.,  when 
mixed  in  certain  pro- 
portions, may  be  used 
for  producing  yielding 
or  elastic  cements.  Of 
whatever  the  cement 
be  composed,  to  be  a 
practical  success  it 
must  not  be  costly,  must  be  durable,  must  not  creep  or  melt 
unless  subjected  to  a  high  temperature,  the  joints  must  be  easy 
to  make,  and  the  cement  must  not  expand  or  contract  so  as 
to  interfere  with  the  soundness  of  a  joint.  Elastic  cements 
may  be  made  by  erecting  a  suitable  size  of  cauldron  in  which 
the  necessary  ingredients  can  be  heated  and  mixed  together. 

As  the  success  of  a  cement  depends  upon  the  ingredients 
used,  and  the  proportions  in  which  they  are  mixed  together, 
experiments  should  be  conducted  on  a  small  scale  until  a 
satisfactory  cement  is  produced. 

The  following  ingredients  will  produce  an  elastic  cement 
suitable  for  drain  pipes  : — 

10  parts  by  weight  of  mastic  asphalt. 
5  parts   „        „        „  coal-tar  pitch. 
5  parts  „        „        „  fine  sand. 


FIG.  85. — Patent  joint. 


PIPE   JOINTS  123 

To  make  the  joints,  a  continuous  stream  of  molten 
cement  should  be  run  into  the  sockets  until  they  are  filled, 
and  the  soundness  of  the  joints  is  improved  by  smearing 
the  socket  and  spigot  ends  with  the  heated  composition 
before  laying  the  pipes  in  position. 


CHAPTEE    V 


SOLDERS,    FLUXES,    AND   LEAD    BURNING 

Soft  Solders. — The  soft  solders  used  by  plumbers  are  alloys, 
composed  principally  of  lead  and  tin,  and  these  metals  are 
mixed  in  varying  proportions  according  to  the  class  of 
solder  required. 

Very  fusible  solders  are  produced  by  adding  bismuth  to 
the  above. 

The  composition  and  fusing  temperatures  of  a  few  soft 
solders  are  as  follows  : — 


Composition. 

Solder. 

Fusing 
Point. 

Tin. 

Lead. 

Bismuth. 

Cadmium. 

Very   fine   (Wood's 

alloy)          ,        . 

4 

8 

15 

3 

158°  Fahr. 

Very  fine 

3 

5 

8 

... 

203°      „ 

55              5)                     • 

1 

2 

i 

300°      „ 

55               )  >                     '                   ' 

3 

2 

1    334°      ,, 

»5              55                     '                   ' 

2 

1 

i    340°      ,, 

Fine     for     general 

work  .         .         .   |        1 

1 

i    370°      „ 

Fine     for     general 

work  . 

8               7 

... 

Wiping  solder 

1 

2 

... 

441°'"  ,, 

The  chief  property  of  very  fine  solder  is  its  low  melting 
point. 

Ordinary  fine  solder  possesses  the  special  property  which 
allows  it  to  be  readily  "  floated  "  so  as  to  form  a  smooth  and 
level  seam. 

Excess  of  tin  in  fine  solder  causes  the  latter  to  have  a 
rough  appearance. 


124 


SOLDERS,    FLUXES,    AND    LEAD   BURNING  125 

The  property  which  makes  plumbers'  or  wiping  solder  so 
useful  for  making  joints  is  the  plastic  state  in  which  it 
remains  when  cooling  through  a  certain  range  of  temperature. 

Much  of  the  solder  at  the  present  time  is  not  made  by 
plumbers  themselves,  and  unless  soft  pig  lead  can  be  readily 
procured  for  its  manufacture  it  is  usually  better  to  purchase 
a  reliable  brand  of  solder  than  to  make  it. 

Much  of  the  sheet  lead,  from  which  solder  is  made  in  the 
workshop,  is  not  produced  from  pure  pig  lead,  and  frequently 
it  contains  impurity  which  has  a  detrimental  effect  upon  the 
solder  made  from  it. 

When  making  plumbers'  solder,  the  lead  and  tin  should 
be  weighed  out  in  proper  proportions,  and  the  lead  should 
first  be  melted  in  a  suitable  cauldron  and  raised  to  a 
moderate  temperature.  The  dross  which  forms  on  .the 
surface  of  the  lead  should  be  skimmed  off,  and  the  tin  then 
added.  As  soon  as  the  tin  is  melted  the  two  metals  require 
to  be  thoroughly  mixed,  and  afterwards  tested  by  pouring  to 
form  several  pats  on  a  clean  cold  stone.  If  the  upper 
surface  of  the  pats  after  cooling  presents  a  white  surface, 
with  several  large  bright  spots,  the  solder  will  be  found 
suitable  for  use.  A  dull  white  surface  without  bright  spots 
indicates  that  the  solder  is  coarse  and  that  more  tin  is 
necessary,  whilst  if  the  surface  of  the  pats  is  covered  with 
numerous  small  bright  spots  the  solder  contains  too  much 
tin. 

It  is  essential  when  pouring  solder  into  moulds  to  keep 
it  well  stirred,  or  that  at  the  lower  part  of  the  cauldron  will 
be  deficient  in  tin. 

Treatment  of  Poisoned  Solder. — As  impurity  in  solder  has 
a  very  prejudicial  effect  upon  its  working  qualities,  every 
precaution  should  be  taken  to  prevent  brass  filings  and  other 
particles  of  foreign  matter  from  getting  into  it.  Zinc  is  the 
worst  form  of  impurity  in  solder,  and  this  metal  may  be 
introduced  in  the  form  of  brass  filings,  or  by  tinning  brass- 
work  by  dipping  it  into  the  solder,  or  by  pouring  solder  over 
brasswork  when  joining  the  latter  to  lead  pipes. 

There  are  two  principal  methods  for  purifying  poisoned 
solder.  The  first  consists  of  melting  the  solder,  when  some 


126     DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 

crushed  rock  sulphur  is  added;  the  pot  should  be  removed 
from  the  fire,  and  the  sulphur  thoroughly  mixed  with  the 
solder  by  stirring.  The  pot  is  afterwards  replaced  on  the 
fire,  and  the  solder  slowly  raised  in  temperature  until  dull 
redness  is  obtained. 

During  the  reheating  process  the  sulphur  combines  with 
the  impurity  in  the  solder,  and  these  rise  together  with 
particles  of  lead  and  tin  to  form  a  thick  scum  on  the  surface 
of  the  solder.  The  scum  or  crust  should  be  entirely  removed 
and  the  solder  afterwards  cleared  by  adding  a  little  resin. 
A  little  tin  may  also  be  necessary,  but  this  can  be  readily 
ascertained  by  testing  the  solder. 

In  the  second  method,  after  the  solder  is  melted  it  is 
poured  on  to  a  clean  iron  tray  (a  porcelain  one  would  be 
preferable),  and  as  it  begins  to  set  it  is  broken  up  into  as 
many  small  particles  as  practicable.  The  poisoned  solder  is 
then  covered  with  diluted  hydrochloric  acid  and  left  submerged 
for  about  an  hour.  Any  particles  of  zinc  are  readily  acted 
upon  by  the  acid,  and  the  solder  afterwards  requires  to  be 
well  washed  to  free  it  from  chloride  of  zinc.  To  finally  clear 
the  solder,  it  is  reheated  and  a  little  resin  added  as  in  the 
first  method. 

Hard  Solders. — Hard  or  brazing  solders  are  those  which 
require  heating  to  redness  before  they  can  be  fused ;  they  are 
used  for  joining  the  harder  metals  and  alloys,  such  as  steel, 
copper,  brass,  gun-metal,  etc.  Although  brazing  has  not  been 
much  in  request  in  plumbers'  work,  it  is  very  probable  that 
it  will  become  more  general  in  the  near  future,  owing  to  the 
displacement  of  lead  waste  pipes  in  the  best  class  of  buildings 
by  light  copper  pipes. 

Brazed  joints  in  connection  with  copper  waste-pipe  work 
would  allow  of  more  simple  forms  of  fittings  being  adopted 
than  many  of  those  used  at  the  present  time. 

Brazing  may  be  done  by  heating  to  a  suitable  tempera- 
ture the  metals  to  be  joined,  either  with  a  bright  hot  fire  or 
with  a  powerful  gas  blow-pipe.  The  surfaces  to  be  brazed 
are  prepared  by  filing  them  clean,  and  the  hard  solder  is 
used  in  a  granular  form  with  powdered  borax  as  a  flux. 
After  the  parts  to  be  joined  have  been  prepared,  the  flux 


SOLDERS,    FLUXES,    AND    LEAD    BURNING 


127 


and  granulated  spelter  are  placed  on  the  joint,  and  heat 
applied  until  the  spelter  floats  round  the  joint,  in  a  similar 
manner  to  that  in  which  fine  solder  is  used  for  jointing 
lead  pipes. 

When  brazing  brass  fittings  and  copper  pipes  together 
some  protection  must  be  afforded  the  brasswork,  or  the  latter 
may  be  fused  when  making  the  joints,  as  the  composition  of 
brass  fittings  may  not  differ  very  much  from  that  of  the 
spelter  used. 

Brasswork  is  readily  protected  from  fusing  by  plastering 
it  over  with  clay,  excepting  the  surfaces  which  are  to  be 
brazed. 

Gas  blow-pipes  are  very  useful  and  convenient  for  light 
brazing,  and  especially  when  oxygen  is  used  in  lieu  of 
atmospheric  air. 

Heat  of  greater  intensity  may  be  obtained  by  the  use  of 
acetylene  and  oxygen. 

The  composition  of  hard  solders  or  spelter  necessarily  vary 
according  to  the  surfaces  to  be  brazed. 


Composition. 

Spelter. 

Copper. 

Zinc. 

Tin. 

Hardest  for  iron  and  steel 

2 

1 

Hard  for  copper,  gun-metal,  and  hard  brass  . 

1 

1 

Soft  for  soft  brass        .... 

4 

a          , 

Fluxes. — The  principal  uses  of  fluxes  when  soldering 
are :  to  prevent  the  oxidation  of  the  prepared  surfaces  so 
as  to  enable  a  sound  joint  to  be  made,  to  assist  the 
solder  to  flow,  and  to  aid  in  cleansing  the  surfaces  to  be 
soldered. 

One  flux  is  found  to  be  more  suitable  than  another 
when  soldering  certain  metals,  and  the  following  gives 
the  fluxes  best  suited  for  the  metals  and  alloys  used  in 
plumbers'  work : — 


128     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


Metal  or  Alloy. 

Flux. 

Lead  when  coarse  solder  is  used              . 
Lead  when  fine  solder  is  used 
Zinc  (new)        :  .             . 
Zinc  (old)            .            . 
Brasswork  and  gun  -metal         :  .        •',''• 
Tin  and  pewter   .            ^            ; 
Iron  when  soft  solder  is  used      .             .             . 

Iron,  copper,  and  steel  when  brazed 

Tallow. 
Tallow  and  resin. 
Chloride  of  zinc. 
Hydrochloric  acid. 
Resin. 
Sweet  oil. 
Chloride  of  zinc   or  sal- 
ammoniac. 
Borax. 

Lead  Burning. — This  is  a  term  which  denotes  the  uniting 
of  two  or  more  pieces  of  lead  by  fusion,  and  without  the 
aid  of  either  a  flux  or  alloy.  The  cost  of  jointing  sheet 
lead  by  "  burning "  is  small  when  compared  with  that  of 
soldering,  and  as  sheet  lead  can  be  effectively  jointed  by 
"  burning,"  the  latter  mode  of  jointing  is  rapidly  gaining 
favour. 

Lead  burning  is  accomplished  by  combining  two  gases 
which  produce  upon  ignition  a  hot  clean  flame.  The  mixed 
gases  are  delivered  at  a  nozzle  or  nipple,  and  the  size  of  the 
flame  is  adjusted  and  directed  on  the  surfaces  to  be  joined, 
and  fused  together  a  little  at  a  time. 

There  are  three  different  mixtures  or  combinations  of 
gases  used  for  lead  burning  purposes — 

(a)  Pure  hydrogen  gas  and  atmospheric  air. 
(&)  Coal-gas  and  atmospheric  air. 
(c)  Pure  hydrogen  and  oxygen. 

When  hydrogen  and  air  are  used,  the  former  is  usually 
generated  in  a  machine,  the  latter  being  delivered  from  a 
container  which  is  charged  by  means  of  a  force  pump. 

When  coal-gas  and  oxygen  are  used,  the  former  is  obtained 
from  the  nearest  available  gas  pipe,  whilst  oxygen  may  be 
obtained  compressed  in  strong  steel  cylinders. 

Compressed  hydrogen  and  coal-gas  may  also  be  obtained 
in  cylinders  if  desired. 

A  complete  arrangement  for  lead  burning  is  shown  in 
Fig.  86,  the  hydrogen  generator  being  on  the  left  side,  and 
the  apparatus  for  supplying  air  on  the  right  side  of  the 
figure.  For  a  small  generator  a  suitable  size  is  10  inches 


SOLDERS,    FLUXES,    AND    LEAD    BURNING 


129 


square,  and  the  chambers  A  and  B  may  be  each  about  1  ft. 
3  in.  high. 

The  whole  of  the  generator  should  be  made  of  lead, 
but  when  it  is  intended  to  be  a  portable  one  it  will  require 
protecting  by  a  suitable  casing  as  shown.  The  upper 
chamber  A  is  made  separate  from  the  lower  one,  and  may 
be  removed  after  taking  the  joint  J  apart. 


"-NIPPLE 
Fio.  86. — Hydrogen  generator  and  air  tank. 

Between  the  large  chambers  A  and  B,  a  small  compart- 
ment or  safety  chamber  C  may  be  provided  of  say  4  inches 
diameter.  A  lead  grate  G,  which  is  perforated  with  J  inch 
holes  and  1J  inches  apart,  is  fixed  about  2  inches  above  the 
bottom  of  chamber  B. 

At  S  a  5  inch  gun-metal  screw  cap  is  required,  and  a 
washout  at  M,  which  is  closed  when  the  machine  is  in  use 
9 


130     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

by  means  of  a  wood  plug.  A  pipe  P  of  1  inch  or  1J  inches 
diameter  communicates  with  the  upper  and  lower  chambers, 
and  the  bottom  of  the  pipe  should  terminate  not  less  than 
1  inch  clear  of  under  surface  of  the  grate  G.  From  the  top 
of  chamber  B  a  |-inch  pipe  is  taken  and  turned  through  into 
the  safety  chamber  C,  and  continued  nearly  down  to  the 
bottom  as  shown.  A  small  cock  D  may  also  be  fixed,  so  as 
to  regulate  the  height  of  the  water  in  the  safety  chamber  C. 

To  charge  a  generator,  a  few  pounds  of  zinc,  which  is 
broken  into  small  pieces,  are  distributed  over  the  grating  G, 
and  the  screw  cap  S  replaced  and  made  air-tight.  The  cock 
at  H  is  closed,  and  into  the  upper  compartment  A  water  is 
poured.  Some  of  the  water  enters  the  lower  chamber  through 
pipe  P,  but  its  entry  is  soon  prevented  owing  to  the  air  in 
B  being  unable  to  escape.  To  each  gallon  of  water  about 
three-quarters  of  a  pint  of  strong  vitriol  (sulphuric  acid)  is 
afterwards  added,  so  as  to  well  mix  with  the  water  in  A. 
The  cock  H  is  now  opened,  the  confined  air  escapes,  and 
the  diluted  acid  flows  into  B  and  submerges  the  spelter, 
when  the  generation  of  hydrogen  begins.  As  soon  as  all 
air  is  displaced  from  the  generator,  hydrogen  gas  is  avail- 
able for  burning.  It  is  essential  when  charging  a  generator 
that  the  water  and  acid  are  added  in  the  order  described, 
for  if  the  acid  were  first  added  an  explosion  would  result. 

The  reason  why  pipe  P  dips  below  the  grate  G  is  to 
enable  the  production  of  hydrogen  to  be  controlled.  When 
the  gas  begins  to  accumulate  and  to  generate  pressure,  it 
displaces  the  dilute  acid  from  B  back  into  A  until  the  acid 
is  clear  of  the  zinc,  when  the  evolution  of  hydrogen  is 
automatically  stopped.  At  the  same  time  the  end  of  the 
pipe  below  G  remains  sealed,  and  waste  is  prevented,  as  the 
gas  is  unable  to  escape.  It  will  thus  be  seen  that  when  a 
generator  is  in  use  the  diluted  acid  in  A  rises  and  falls 
according  to  the  rate  the  gas  is  used. 

Care  is  necessary  in  the  management  of  a  generator  if 
it  is  to  work  satisfactorily.  Each  day  after  use  the  spent 
or  dilute  acid  should  be  discharged,  and  the  generator  well 
washed  out  with  clean  water.  Instead  of  a  wood  outlet  plug 
M,  a  stoneware  cock  may  be  used,  but  the  former  is  more 


SOLDERS,    FLUXES,    AND    LEAD    BURNING  131 

satisfactory  for  a  portable  machine,  as  the  latter  is  liable 
to  be  broken.  The  zinc  should  be  broken  into  small  pieces, 
as  a  greater  surface  is  exposed  to  the  action  of  the  acid 
than  when  large  pieces  are  used.  When  a  generator  is  not 
regularly  cleansed,  sulphate  of  zinc  begins  to  crystallise  and 
to  choke  up  the  pipe  P.  Crystals  also  form  on  the  surface 
of  the  zinc  and  prevent  the  free  generation  of  hydrogen. 

Should  a  generator,  however,  be  allowed  to  get  in  such 
a  state,  the  trouble  can  be  overcome  by  washing  it  out  with 
hot  water,  which  dissolves  the  crystals  formed.  The  purpose 
of  the  safety  chamber  C  is  to  prevent  the  generator  being 
damaged  by  explosion  should  a  light  be  applied  before  all 
atmospheric  air  has  been  dislodged.  Hydrogen  alone  cannot 
explode,  but  when  mixed  with  a  certain  volume  of  air  an 
explosive  mixture  is  produced.  If  through  ignorance  or 
carelessness  a  light  should  be  applied  to  the  nipple  before 
the  air  is  removed,  damage  by  explosion  would  be  chiefly 
Confined  to  the  safety  chamber,  as  the  direct  passage  between 
it  and  B  is  broken  by  the  water  seal,  owing  to  the  gas  first 
requiring  to  bubble  through  the  water  before  it  can  be 
delivered  to  the  tubes.  The  lead  for  a  safety  chamber 
should  only  be  thin,  and  4-lb.  lead  is  suitable  for  the 
purpose. 

The  tank  for  supplying  air,  Fig.  86,  is  of  simple  con- 
struction, and  is  divided  into  two  compartments  as  shown. 
This  may  be  formed  of  galvanised  sheet  iron,  a  convenient 
size  being  12  to  14  inches  diameter,  and  about  3  feet  in 
height.  The  height  of  the  lower  compartment  should  be  a 
little  less  than  the  upper  one,  in  order  that  water  may  not 
be  projected  from  the  upper  chamber  when  the  container  is 
overcharged  with  air.  The  pipe  X,  Fig.  86,  is  made  to 
communicate  with  the  lower  part  of  each  compartment,  so 
that  water  may  be  displaced  from  the  lower  to  the  upper 
compartment  by  means  of  the  air-pump  Y.  To  prevent 
water  getting  into  the  flexible  tube  and  cutting  off  the  supply 
of  gas,  the  outlet  pipe  0  is  carried  above  the  lower  chamber, 
and  turned  through  the  side  as  in  Fig.  86. 

For  maintaining  a  steady  pressure  of  air,  which  is 
essential  for  good  burning,  the  water  in  the  upper  compart- 


132     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


ment  is  often  maintained  at  a  constant  level  by  continuous 
pumping. 

After  a  generator  and  air  container  have  been  charged, 
the  gases  are  led  through  rubber  tubes  of  any  convenient 
length  to  a  breeches  piece  N,  which  is  provided  with 
regulating  cocks.  To  the  outlet  of  the  breeches  piece  a 
few  feet  of  mixing  tube  are  joined,  and  to  the  other  end  of 
the  mixing  tube  a  brass  tube  is  inserted  on  which  various 
sizes  of  nipples  can  be  screwed. 

Lead  burning  is  generally  classified  under  four  heads, 
according  to  the  positions  in  which  joints  in  sheet  leadwork 
are  made.  These  are  as  follows :  Flat  burning,  horizontal 
burning,  upright  burning,  and  overhead  burning.  In  flat 


IS 
FIG.  87. — Examples  of  lead  burning. 

burning  the  edges  to  be  fused  may  either  be  placed  edge  to 
edge  or  overlap  each  other,  as  at  A  and  B,  Fig.  87  ;  in 
both  cases  a  strip  of  lead  is  used  and  a  raised  seam  formed. 

Flat  burning  is  the  easiest  kind  of  "  burning,"  and  is  soon 
learned,  but  great  care  is  necessary  in  the  early  stages,  for 
at  every  point  the  lead  must  be  properly  fused  or  defects 
may  arise  which  are  difficult  to  locate. 

For  burning  a  very  hot,  pointed  flame  is  required,  in  order 
that  the  lead  may  be  fused  at  any  point  without  first  heating 
the  surface  surrounding  it. 

Lead  strips  for  burning  are  usually  of  the  form  shown 
at  E,  Fig.  87,  and  are  cast  in  clean  iron  moulds  which 
may  be  obtained  at  a  cost  of  a  few  shillings. 

A  sample  of  horizontal  burning  is  shown  at  C,  and  a 
lead  strip  is  used  to  make  the  joint  provided  the  edges 


SOLDERS,    FLUXES,    AND    LEAD   BURNING  133 

of  the  lead  are  thick  enough  to  permit  of  it.  For  thin  lead 
the  overlap  is  simply  fused  with  the  lead  behind  it. 

Upright  burning  D,  Fig.  87,  is  much  more  difficult  than 
either  flat  or  horizontal  burning,  and  a  smaller  flame  is 
required.  The  edge  of  the  overlap  is  fused  with  the  lead 
behind  it,  the  burning  being  commenced  at  the  bottom  as 
indicated  in  the  figure.  The  joints  of  upright  burning  are 
much  narrower  than  those  of  flat  burning,  and  much  smaller 
beads  are  formed. 

Overhead  burning  is  the  most  difficult  to  accomplish, 
but  in  ordinary  plumbers'  work  it  is  very  rarely  if  ever 
required.  Plumbers  in  chemical  works  and  similar  places 


FIG.  88. — Apparatus  for  lead  burning. 

are  occasionally  required  to  do  overhead  burning,  but  not 
nearly  so  often  as  is  generally  supposed. 

Where  coal-gas  is  available,  and  compressed  oxygen  is 
used,  the  apparatus  for  lead  burning  may  take  the  simple 
form  given  in  Fig.  88. 

A  cylinder  when  fully  charged  with  oxygen  is  subjected 
to  an  internal  pressure  of  120  atmospheres,  or  say  1800  Ib. 
per  sq.  inch.  As  the  gas  leaves  the  cylinder  it  may  be 
reduced  in  pressure  with  a  special  form  of  automatic  regulator, 
and  the  arrangement  of  tubing  and  common  nipple  adopted 
as  in  Fig.  86.  When,  however,  compressed  gases  are  used 
an  injector  form  of  blow- pipe  is  more  suitable,  and  the  gas 
from  the  cylinder  may  be  regulated  by  a  simple  pattern  of 
adjustment  valve. 

In  Fig.   88,  V  represents  the  cylinder  valve;   the    fine 


134     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

adjustment  valve  is  indicated  by  A,  and  by  it  the  necessary 
amount  of  oxygen  is  admitted  to  the  tubes,  and  without 
subjecting  them  to  undue  pressure.  As  the  valve  A  takes 
the  place  of  an  automatic  regulator,  care  is  necessary, 
however,  in  its  manipulation.  The  rubber  tube  from  the 
oxygen  cylinder  is  joined  with  the  injector  side  of  the  blow- 
pipe, and  the  oxygen  and  coal-gas  mix  in  flowing  towards 
the  nipple. 

A  good  size  of  cylinder  for  workshop  use  is  one  holding 
40  cubic  feet  of  oxygen  when  under  the  maximum  pressure 
of  1800  Ib.  per  sq.  inch,  but  a  20  feet  size  is  more  suitable 
in  other  cases,  as  the  weight  of  the  larger  cylinder  is  about 
60  Ib. 

Oxygen  for  lead  burning  purposes  can  be  obtained  at  the 
reduced  rate  of  Ifd.  per  cubic  foot  in  40 -feet  cylinders, 
and  at  1-J-d.  per  foot  in  20 -feet  cylinders.  In  country 
districts  the  cost  of  carriage  would  require  to  be  added. 

The  amount  of  oxygen  consumed  varies  with  the  kind  of 
burning,  but  the  average  consumption  may  be  taken  at 
1  cubic  foot  per  burner  per  hour. 

Fig.  88  shows  an  apparatus  which  is  very  suitable  for 
ordinary  plumbers'  use,  and  the  initial  outlay  is  only  about 
one-third  that  for  the  generator  and  air  cylinder  given  in 
Fig.  86. 

Gases  when  compressed  in  cylinders  are  extremely  useful 
for  burning  sheet  leadwork  on  roofs,  such  as  that  on  finials, 
stone  cornices,  etc.,  and  for  burning  the  joints  of  lead-lined 
cisterns. 

A  very  strong  rubber  tube  is  required  for  the  oxygen 
connection,  as  this  tube  is  subjected  to  a  moderate  pressure. 

The  only  preparation  required  for  "  burning "  is  the 
shaving  of  the  surfaces,  and  this  should  be  neatly  done. 
Neither  flux  nor  plumbers'  black  is  required. 

To  line  large  cisterns  with  lead  where  the  joints  are 
burned,  the  lead  should  be  arranged  so  that  all  the  joints 
come  on  flat  surfaces  about  1-J  inches  or  so  from  the  angles. 
The  lead  for  the  sides  of  the  cisterns  should  be  turned 
inwards  along  their  bottom  edges,  in  order  that  the  sides 
and  bottoms  may  be  joined  with  flat  burning. 


UNIVHKO1  I  T 

OF 


SOLDERS,  FLUXES,  AND  LEAD  BURNING     135 

For  small  cisterns  which  are  easy  to  handle  the  burning 
may  be  done  at  their  angles  if  desired.  A  strip  of  lead 
should  be  used  wherever  possible,  as  much  stronger  joints 
are  made  than  where  two  surfaces  are  simply  fused 
together. 


CHAPTER    VI 
SANITARY   FITTINGS   AND   ACCESSORIES 

SANITARY  fitting  is  a  very  comprehensive  term,  but  in  this 
chapter  its  use  is  limited. 

Owing  to  the  rapid  advances  which  have  taken  place  in 
sanitary  science,  very  little  space  will  be  devoted  to  what 
are  now  obsolete  appliances. 

The  general  principles  which  should  govern  the  con- 
struction of  sanitary  fittings  are  as  follows :  (a)  Simplicity 
of  form,  being  free  from  complicated  and  not  readily  accessible 
parts,  (b)  They  should  be  made  of  hard,  durable  material, 
with  smooth  and  well  glazed  surfaces,  so  as  to  be  practically 
non-porous,  (c)  The  design  should  not  admit  of  unnecessary 
surfaces  which  are  liable  to  collect  dirt,  and  which  require  a 
lot  of  attention  to  keep  them  in  a  cleanly  state,  (d)  Their 
outlets  should  be  formed  to  enable  reliable  and  simple  con- 
nections to  be  made  with  the  pipes  into  which  they 
discharge. 

Water  Closets. — The  best  w.c.'s  at  the  present  time  are 
the  "  wash-down  "  and  "  siphonic  "  types.  There  are  patterns 
of  these,  however,  that  are  not  free  from  structural  defects, 
but  there  is  no  difficulty  in  procuring  a  first-class  article 
from  a  good  manufacturer  provided  a  reasonable  price  is  paid 
for  it.  Other  types  of  w.c.'s  are  very  inferior  to  those 
already  named,  and  a  few  will  be  described  and  their 
principal  defects  noted. 

An  ideal  w.c.,  besides  satisfying  the  general  conditions 
enumerated  above,  should  be  thoroughly  cleansed  with  one 
flush  of  water,  have  a  small  amount  of  dry  basin  surface 
exposed  to  contamination,  hold  sufficient  water  to  completely 
submerge  all  excrernental  matter,  and  be  trapped  in  such 


136 


SANITARY    FITTINGS   AND   ACCESSORIES 


137 


a  manner  that  an  effective  barrier  is  formed  to  prevent  the 
passage  of  drain  air  into  the  w.c.  apartment. 

All  w.c/s  which  require  wood  or  other  enclosures,  with  the 
exception  of  the  valve  closet,  are  obsolete,  the  pedestal  form 
taking  the  place  of  those  in  which  basins  and  traps  were 
made  in  separate  parts. 

Wash-out  Type. — The  wash-out  w.c.,  Fig.  89,  is  a  defective 
form  of  the  pedestal  class.  The  part  which  acts  as  a  receiver 
destroys  the  force  of  the  flushing  water,  with  the  result  that 
excrement  accumulates  on  the  imperfectly  flushed  surfaces  on 
the  inlet  side  of  the  trap,  and  matter  is  also  frequently  left 
lodging  in  the  trap.  In  certain  cases  where  wash-out  w.c/s 
have  been  fixed  it  has  been  essential  to  replace  them  with  a 
better  type  within  half  a  dozen 
years  of  instalment. 

Wash  -  down  Type. — For  a 
simple  form  of  w.c.  there  is 
nothing  better  at  present  than 
the  wash-down  type,  when  well 
designed  and  supplied  with  an 
adequate  flush  of  water.  In  the 
wash-down  w.c.  the  full  force  of 
the  flushing  water  is  utilised  to 
cleanse  the  basin  and  trap. 

There  are  many  different 
wash-down  w.c.'s  that  vary  in  constructional 


—"Wash-out  w.c. 


details,  such 

as  in  the  size  and  shapes  of  basin,  size  of  water  surface, 
positions  of  outlets,  depth  of  water  seal,  and  the  form  of 
flushing  rim. 

The  size  and  shape  of  a  w.c.  is  of  considerable  import- 
ance, for  upon  these  its  efficiency  largely  depends,  and 
especially  when  flushed  with  a  limited  volume  of  water. 

Wash-down  w.c.'s.  with  receding  backs  are,  as  a  rule, 
objectionable,  as  these  surfaces  when  fouled  are  not  always 
thoroughly  cleansed.  The  depth  of  water  seal  in  the  trap  of 
a  wash-down  w.c.  is  limited,  for  when  it  exceeds  2  inches 
considerable  resistance  is  offered  by  a  trap,  and  frequently 
the  effective  removal  of  excrement  with  one  flush  is  uncertain. 
On  the  other  hand,  the  water  seal  of  a  trap  should  not  be  less 


138     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


than  2  inches  deep  in  order  to  ensure  a  safe  barrier  against 
the  passage  of  contaminated  air  when  the  seal  has  been 
reduced  a  little  by  waving  out,  or  by  evaporation,  etc. 

A  large  water  area  in  a  basin  is  always  desirable,  but  this 
in  turn  is  limited  by  the  form  the  basin  takes  and  by  the 
volume  of  water  used  for  each  flush.  Thus,  when  a  water 
surface  is  comparatively  large,  and  when  a  trap  has  a  2-inch 
seal,  not  less  than  three  gallons  of  water  will  be  required  for 
scouring  out  the  w.c. 

A  wash -down  w.c.  that  is  most  easily  cleansed  is  one 
that  is  comparatively  small  in  size,  where  the  water  surface 
in  the  basin  is  small,  and  where  the  trap  holds  the  minimum 
volume  of  water  and  has  a  small  seal.  Some  of  the  w.c.'s 

constructed  in  this 
manner  can  be  cleansed 
with  two  gallons  of 
water  and  less,  al- 
though such  volumes 
are  insufficient  to 
cleanse  the  drains  into 
which  the  w.c.'s  dis- 
charge. 

Doulton's  simpli- 
citas  w.c.  is  illustrated 
in  Fig.  90  ;  the  back 

is  constructed  fairly  straight,  so  as  to  minimise  the  risk 
of  soiling  it.  The  general  construction  of  the  basin  is  such 
as  to  limit  the  water  area  in  the  trap,  in  order  that  the 
w.c.  may  be  flushed  with  two  gallons  of  water.  The  outgo 
is  well  above  the  floor,  and  admits  of  a  reliable  connection 
being  made  with  the  branch  soil  pipe. 

Fig.  91  gives  another  wash-down  w.c.  by  the  same 
makers.  The  front  of  the  basin  in  this  case  is  not  curved  to 
the  same  extent  as  in  the  one  previously  shown,  and  the 
w.c.  has  a  larger  exposed  water  area.  This  form  of  con- 
struction also  has  less  surface  that  is  liable  to  be  fouled  when 
compared  with  that  of  Fig.  90,  but  on  account  of  the  extra 
resistance  offered  by  the  increased  volume  of  water  in  the 
trap  not  less  than  a  three-gallon  flush  will  be  required  to 


FIG.  90. — Wash-down  w.c.  (Doulton's 
"Simplicitas.") 


SANITARY   FITTINGS   AND   ACCESSORIES 


139 


give  satisfactory  results.  To  the  outlet  of  Fig.  9 1  is  attached 
the  firm's  patent  Metallo-Keramic  joint,  so  that  an  easy  and 
safe  connection  can  be  made  with  a  lead  soil  pipe.  The 
connecting  piece  consists  of  a  short  piece  of  lead  pipe  which  is 


Soi.orR 


FIG.  91. — Wash-down  w.c. 

soldered  to  the  outgo  of  the  w.c.  To  enable  a  lead  pipe  to 
be  soldered  to  the  pottery  ware,  a  metallic  film  is  deposited 
on  the  outgo,  and  is  afterwards  fired  to  thoroughly  fix  it. 
The  lead  pipe  is  then  soldered  to  the  metallic  film. 

Shanks'     "Modern"   w.c.,    Fig.    92,   differs    slightly  in 


FIG.  92.— Wash-down  w.c.  (Shanks'  "Modern.") 

construction  from  those  already  shown.  The  back  of  this 
closet  recedes  a  little  to  prevent  its  getting  soiled,  and 
although  receding  backs  are  not  generally  a  success,  the  one 
shown  is  an  exception  to  the  rule  on  account  of  the  special 
design  of  the  basin  and  the  form  of  flushing  rim  adopted. 


140     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


The  exposed  water  surface  is  of  medium  size,  and  the  w.c. 
can  be  cleansed  with  a  two-gallon  flush,  although  for  reasons 
previously  stated  a  larger  flush  is  desirable. 

It  will  generally  be  found  that  wash-down  w.c.'s  with  S 
traps  are  more  easily  cleansed  than  those  with  P  traps, 
owing  to  the  outlets  of  the  former  admitting  of  a  freer  dis- 
charge. For  the  poorer  and  cheap  grades  of  wash-down  w.c.'s 
those  with  S  traps  should  be  used  wherever  practicable,  as 
those  with  P  traps  often  have  their  outlets  badly  formed, 
and  with  little  or  no  pitch. 

A  shape  of  w.c.  that  will  permit  of  a  2J  to  a  3-inch 
seal,  and  be  cleansed  with  a  two-gallon  flush,  is  given  in 
Fig.  93.  It  will  be  observed  that  in  order  to  satisfy  these 

conditions  both  the  basin 
and  water  surface  are  of 
restricted  size. 

Flush  Pipes  should  be  as 
free  from  bends  as  possible, 
and  the  height  of  a  flushing 
cistern  need  not  be  more 
than  6  feet  above  the  flush- 
ing rim  of  a  w.c.  When 
flush  pipes  are  1^  inches 
FIG.  93.— Wash-down  w.c.  diameter,  and  fairly  straight, 

a  flushing  head  of  5  ft.  6  in. 

gives  very  good  results.  Unless  flush  pipes  are  long,  a 
greater  head  than  6  feet  usually  causes  water  to  be  projected 
on  the  floor  of  the  apartment  or  on  to  the  w.c.  seat. 

In  situations  where  a  flushing  head  is  limited  to  about 
4  feet,  and  a  wash-down  w.c.  is  to  be  fixed,  care  should  be 
taken  to  select  a  small  pattern  or  it  may  not  be  cleansed  with 
one  flush  of  water. 

For  hospital  use  w.c.'s  are  frequently  constructed  to 
enable  them  to  be  fixed  clear  of  floors,  by  building  into  the 
walls  corbels  which  form  parts  of  the  closets  used.  Such 
w.c.'s  are  also  utilised  in  other  public  institutions  where 
cleanliness  is  of  paramount  importance. 

Combination  Closets. — For  situations  where  there  is  in- 
sufficient space  to  fix  overhead  cisterns  the  combination  w.c. 


SANITARY   FITTINGS   AND    ACCESSORIES  141 

may  be  used.  The  flushing  rims  of.  the  basins  require  to  be 
moderately  large,  and  the  outlets  of  the  cisterns  are  much 
larger  than  those  of  overhead  cisterns.  On  account  of  their 
silent  action  combination  closets  have  been  used  in  lieu  of 
those  with  overhead  cisterns,  but  as  regards  their  general 
efficiency  they  are  often  inferior  to  the  latter  provided  the 
flushing  cisterns  are  fixed  at  suitable  heights.  The  larger 
inlets  of  combination  forms,  and  other  features,  do  not  com- 
pensate for  a  reasonable  flushing  head  of  the  ordinary  type. 

Valve  Closets. — The  valve  closet  possesses  some  good 
points  which  are  absent  in  a  wash-down  type,  but  the  former 
has  also  failings  from  which  the  latter  is  free.  The  principal 
merits  of  valve  closets  are:  (1)  The  large  volume  of  water 
held  up  in  the  basins ;  (2)  The  small  area  of  basin  surface 
liable  to  be  fouled ;  (3)  The  flushing  power  of  the  water  in  the 
basins  when  suddenly  released. 

The  drawbacks  of  valve  closets  are :  (1)  Their  compli- 
cated construction ;  (2)  The  mechanism  in  connection  with 
them  is  liable  to  get  out  of  order ;  (3)  They  are  costly ;  (4) 
They  may  require  to  be  enclosed  with  casings,  and  filth  may 
be  allowed  to  accumulate  and  remain  hidden  from  view. 

When  a  valve  closet  is  fixed  upon  a  wood  floor,  a  lead 
tray  or  safe  should  be  placed  beneath  it.  The  valve  box  and 
trap  may  either  be  obtained  in  one  piece  of  pottery  ware,  and 
with  the  whole  of  the  closet  placed  above  the  floor,  or  the 
valve  box  and  trap  may  be  had  in  separate  parts ;  in  the 
latter  case  the  trap  may  be  of  lead  and  fixed  beneath  the 
floor,  and  the  valve  box  may  be  either  of  cast  iron,  porcelain 
enamelled  inside,  or  of  lead. 

A  source  of  weakness  with  the  early  forms  of  valve 
closets  was  in  connection  with  their  overflows,  but  this  draw-, 
back  is  practically  overcome  in  modern  fittings,  where  the 
overflows  are  open  and  washed  out  each  time  the  closets  are 
flushed.  The  valve  box  is  made  as  small  as  possible,  and 
provision  is  made  for  ventilating  it.  Fig.  94  gives  a  modern 
form  of  valve  closet,  and  the  trapping  and  general  arrange- 
ment of  the  overflow  are  clearly  shown.  The  recharging  of 
the  basin  is  usually  controlled  by  some  particular  form  of 
regulated  valve,  the  water  overflowing  when  the  water-line  is 


142     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


reached.  Valve  closets  are  largely  used  in  ships,  their  use 
being  essential  in  many  cases  to  prevent  the  backwash  of 
water. 

Siphonic  Closets. — Owing  to  the  limitations  of  both  wash- 
down  and  the  best  forms  of  valve  closets,  the  siphonic  type 
has  been  introduced.  This  form  may  not  at  present  be  the 
acme  of  perfection,  yet  when  constructed  upon  sound  principles 
it  possesses  most  of  the  merits  of  both  the  valve  and  wash- 
down  types. 

Many  siphonic  closets  are  nearly  silent  in  action,  have  a 
quick  and  powerful  discharge,  have  large  water  surfaces  and 

a  minimum  of  fouling 
surface,  and  possess 
the  merit  of  having 
their  contents  with- 
drawn by  siphonage 
instead  of  depending 
upon  their  contents 
being  dislodged  by  the 


VENTILATING 
PIPE  (OKJWECTIONI 


FIG.  94. — Valve  w.c.  where  trap  is  fixed 
beneath  floor. 


force  of  the  flushing 
water,  as  in  the  case 
of  the  wash  -  down 
type. 

A  siphonic  w.c. 
mayalso  have  a  deeper 
seal  than  any  other 
form. 

The  chief  faults  of  siphonic  w.c/s  arise  through  defects  of 
construction  and  not  to  the  general  principle  embodied  in 
them. 

Various  means  have  been  devised  for  starting  siphonic 
action  in  these  closets,  such  as  by  the  introduction  of  jets  or 
peculiarities  of  construction,  and  by  either  the  expulsion  or 
extraction  of  confined  air. 

Many  siphonic  w.c.'s  require  special  flushing  cisterns  to 
work  in  connection  with  them  on  account  of  the  volume  of 
water  necessary  for  recharging  the  basins  after  siphonage  has 
ceased.  There  are  other  siphonic  closets  with  which  any 
ordinary  flushing  cistern  can  be  used,  but  these  usually  hold 


SANITARY    FITTINGS    AND    ACCESSORIES 


143 


SOLDER' 


much  less  water  than  the  first  mentioned.  The  latter  are 
recharged  with  water  as  a  rule  by  means  of  an  after  flush 
compartment  which  forms  part  of  the  closet. 

For  the  purpose  of  comparison  all  siphonic  closets  may  be 
grouped  in  two  classes.  First,  those  that  have  two  traps, 
and  second,  those  with  only  one  trap. 

In  the  double  trapped  class,  siphonage  is  started  either 
by  extracting  or  displacing  air  from  the  limb  that  communi- 
cates with  both  traps.  The  object  is  the  same  in  either  case, 
viz.  to  destroy  the  equilibrium  of  air  pressure  on  the  water 
surface  of  the  basin,  and  of  that  in  the  limb  between  the  two 
traps. 

Siphonage  in  the  sinyle  trapped  type  is  started  by 
momentarily  re-  __ 

tarding  the  first 
outflow  of  water 
through  the  trap, 
by  introducing 
some  particular 
form  of  construc- 
tion, and  with  or 
without  the  aid 
of  a  jet  of  water. 

Shanks' "  Le- 
vern "  siphonic 
closet,  Fig.  95,  is 

an  example  of  the  one-trapped  class.  It  is  simple  in  con- 
struction, has  a  large  water  area  in  the  basin,  very  little 
surface  that  is  liable  to  be  soiled,  and  the  whole  of  the 
flushing  water  passes  through  the  basin.  The  siphonic  action 
is  due  to  the  enlargement  E  in  the  lead  outlet  pipe,  and  is 
established  as  follows :  when  the  closet  is  flushed,  the  water 
follows  the  curved  surface  at  E,  and  owing  to  the  abrupt  change 
of  direction  at  the  bottom  of  the  enlargement  the  water  is 
caused  to  be  projected  towards  the  centre,  and  to  produce  a 
momentary  stoppage  of  the  flow;  the  brief  interval  of 
retardation  is,  however,  sufficient .  to  allow  the  outlet  leg  to 
get  fully  charged,  when  siphonage  is  established,  and  the 
contents  of  the  basin  rapidly  withdrawn.  Provision  is  made 


FIG.  95.— Siphonic  w.c.  (Shanks'  "Levern"). 


144      DOMESTIC    SANITARY  ENGINEERING    AND    PLUMBING 

in  the  flushing  cistern  for  recharging  the  basin  with  water. 
This  design  of  w.c.  admits  of  the  basin  being  emptied  of  water 
if  a  pailful  of  slops  is  emptied  into  it,  but  this  may  be 
counteracted  by  using  an  anti-slop  discharge  attachment  in 
connection  with  the  closet. 

Doulton's  siphonic  w.c.,  Fig.  96,  represents  one  of  the 
double-trapped  class,  and,  like  the  one  previously  shown,  it 
has  a  large  water  surface  and  small  area  that  is  liable  to  be 
soiled.  Siphonage  in  this  case  is  principally  started  by 


FIG.  96. — Doulton's  siphonic  w.c. 

reducing  the  air  pressure  between  the  two  traps  by  means  of 
a  small  pipe  which  communicates  with  the  space  B  and  the 
flush  pipe  or  cistern.  It  is  so  arranged  that  when  the  water 
descends  in  the  flush  pipe,  the  aspirating  effect  produced  is 
transmitted  to  the  limb  B  by  the  pipe  A.  In  this  manner  air 
is  withdrawn  from  the  limb  B,  or  rarefied  to  such  a  degree  that 
unequal  air  pressures  act  upon  the  water  surfaces,  and  cause 
siphonage  to  be  established.  Two  traps  are  of  course  essential 
to  confine  air  for  this  particular  action,  but  the  bottom  trap 
also  aids  to  a  certain  extent  in  starting  siphonage  by  offering 
resistance  at  the  outset  to  the  escaping  water,  and  in  enabling 


SANITARY    FITTINGS    AND   ACCESSORIES 


145 


the  limb  B  to  be  charged  just  prior  to  the  siphonic  action 
being  started.  The  inlet  of  the  lead  trap  T  may  be  obtained 
shorter  when  desired,  to  enable  the  whole  of  the  w<c.  to  be 
above  the  floor. 

Twyford's  siphonic  w.c.,  Fig.  97,  has  only  one  trap,  and  it 
is  arranged  that  a  portion  of  the  flushing  water  passes  through 
the  outlet  from  point  P  in  the  form  of  a  jet,  and  in  the 
direction  shown.  The  jet  of  water  and  the  sharp  elbow 
connection  C  are  responsible  for  establishing  siphonage. 

Sharp  elbows  in  soil  pipes  are  not  usually  desirable,  but 


FIG.  97. — Twyford's  siphonic  w.c. 

in  this  case  the  retardation  offered  by  the  elbow  is  utilised 
to  charge  the  limb  above  point  C,  whilst  the  jet  aids  in 
removing  the  contents  from  the  basin.  The  maximum  resist- 
ance offered  by  the  sharp  elbow  at  C  is  only  for  a  brief 
interval,  after  which  siphonic  action  is  started.  This  closet 
may  also  have  its  outlet  arranged  to  come  above  the  floor 
when  required. 

The  siphonic  w.c.'s  which  have  been  given  indicate 
different  ways  in  which  siphonage  may  be  established.  Most 
makers  of  sanitary  fittings  have  produced  closets  of  the 
siphonic  class,  and  although  they  may  differ  a  little  .in 


10 


146      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

construction,  the  main  features  do  not  differ  much  from  those 
already  shown  and  described. 

In  order  that  a  siphonic  w.c.  may  work  properly,  it  is 
important  that  waste  matter  can  be  freely  discharged  after 
being  admitted  into  the  branch  soil  pipe ;  if  the  outflow  is 
unduly  retarded  there  is  a  possibility  of  the  action  of  the 
closet  being  impaired.  Branch  soil  pipes  in  connection  with 
siphonic  w.c/s  should  be  comparatively  short  and  have  a  good 
pitch. 

Trough  Closets. — For  schools,  factories,  workshops,  etc., 
trough  closets  are  frequently  installed.  These  fittings,  how- 
ever, are  very  objectionable,  as  they  present  large  surfaces  which 
get  fouled  with  excrementitious  matter.  Some  trough  closets 
are  provided  with  flushing  rims,  that  their  surfaces  may  be 
washed  to  more  or  less  extent,  but  the  effective  force  of  the 
flushing  water  is  chiefly  required  to  scour  the  trough  from  end 
to  end.  These  fiUings  can  only  be  placed  in  out-buildings, 
and  are  flushed  at  intervals  by  an  automatic  flushing 
tank. 

Siphonic  Latrines. — A  better  form  of  closet  for  fixing  in 
out-buildings  is  the  siphouic  latrine,  or  isolated  trough 
closet,  Fig.  98.  Like  trough  closets  they  are  automatically 
flushed,  and  can  readily  be  inspected  to  see  if  they  are 
subjected  to  improper  use.  In  Fig.  98  the  basins  are 
provided  with  flushing  rims,  and  are  connected  with  a  hori- 
zontal pipe  common  to  the  whole  range.  To  form  the  water 
seals,  one  end  of  the  collecting  pipe  is  turned  up,  so  that 
water  is  made  to  stand  at  a  given  level  in  the  whole  range. 
When  the  flush  tank  discharges,  siphonic  action  in  the  vertical 
limb  B  is  readily  established,  and  the  contents  of  the  basins 
are  withdrawn.  The  whole  of  the  flushing  water  passes 
through  the  basins,  and  its  full  force  is  utilised  to  cleanse 
their  surfaces.  The  pipe  A,  which  is  joined  near  the  top  of 
the  bend,  is  carried  up  and  turned  over  into  the  flushing  tank 
The  purpose  of  this  pipe  is  to  arrest  siphonage  in  the  limb  B, 
by  allowing  air  to  enter  it,  when  the  water  in  the  flushing 
tank  is  lowered  so  as  to  leave  the  end  of  the  pipe  free.  Below 
the  free  end  of  pipe  A  the  capacity  of  the  flush  tank  requires 
to  be  sufficient  to  recharge  the  whole  of  the  basins  with  water. 


SANITARY   FITTINGS   AND    ACCESSORIES 


147 


The  pipe  A  does  not  interfere  with  the  siphonic  action  of  the 
flushing  tank,  but  only  with  that  in  the  latrine  itself. 

Ranges  of  pedestal  wash-down  closets  may  also  be  fixed, 
and  flushed  by  means  of  one  or  more  automatic  tanks,  instead 
of  providing  a  separate  cistern  for  each  w.c. 

A  drawback  which  is  associated  with  automatically  flushed 
ranges  is  the  large  volume  of  water  used,  and  where  water  is 
an  expensive  item  there  is  often  a  tendency  to  limit  the  number 
of  flushes  and  to  sacrifice  cleanliness. 

Controlling  appliances  are  occasionally  used  in  conjunction 


FIG.  98. — Siphonic  latrine. 

with  siphonic  latrines,  with  a  view  to  reducing  the  con- 
sumption of  water  when  the  conveniences  are  not  in  use. 
These  appliances,  however,  are  not  as  a  rule  reliable,  and  at 
their  best  only  a  partial  success.  For  large  works,  where  an 
attendant  is  placed  in  charge  of  the  sanitary  conveniences,  the 
ordinary  wash-down  type  of  closet  with  separate  flushing 
cistern  is  the  best  to  adopt. 

Connections  of  W.C.'s. — In  the  chapter  on  joints,  a  common 
and  good  form  of  connection  for  the  outlet  of  a  w.c.  and  a 
lead  soil  pipe  branch  is  given.  Flange  joints  which  depend 


148      DOMESTIC   SANITARY    ENGINEERING   AND   PLUMBING 


LEA>D  PIPE 


RPC. 


upon  rubber  rings  for  their  soundness  are  not  always  reliable 
for  the  outgo  of  a  w.c. ;  and  where  space  is  limited  flange 
joints  are  difficult  to  make. 

Special  brass  union  couplings  with  ground  joints  are 
occasionally  used  for  soil  pipe  connections,  to  enable  a  lead 
outlet  bend  to  be  turned  in  any  direction  desired ;  this  form 
of  joint  is  better  when  made  beneath  the  water-line  of  the 
trap,  in  order  that  water  may  drip  on  the  floor  and  indicate 
the  presence  of  a  defect  if  such  occurs. 

Antisiphonage  Pipe  Connec- 
tions.— A  source  of  weakness  in 
many  closets  is  the  connections 
between  the  antisiphonage  pipes 
and  the  ventilating  horns  on 
closets.  In  the  case  of  a  ven- 
tilating horn  being  located  where 
there  may  be  some  degree  of 
uncertainty  in  being  able  to 
make  a  reliable  joint  between  it 
and  the  antisiphonage  pipe,  the 
best  plan  to  adopt  is  to  seal  up 
the  earthenware  horn,  and  to  join 
the  antisiphonage  pipe  at  another 
point.  Unless  a  soil  pipe  is 
periodically  tested,  a  defect  at 
an  antisiphonage  pipe  connection 
may  remain  undetected  for  an 
indefinite  period. 

If  a  vent  horn  is  located  at 
the  crown  of  an  outlet  bend  of  a  w.c.  it  is  liable  to  be 
choked  and  rendered  useless ;  moreover,  if  the  flush  pipe 
also  joins  at  the  back  of  a  closet  with  a  horizontal  con- 
nection, the  two  joints  usually  come  too  close  together  to 
admit  of  their  being  properly  made. 

At  A,  Fig.  99,  an  antisiphonage  pipe  is  shown 
which  is  joined  with  a  ventilating  horn  at  the  side  of 
the  outgo  of  a  w.c.  ;  this  arrangement  keeps  the  anti- 
siphonage pipe  clear  of  the  flush  pipe,  and  admits  of  the 
joint  being  more  readily  made.  A  suitable  jointing  material 


FIG.  99. — Joints  for  antisiphonage 
pipes. 


SANITARY    FITTINGS    AND    ACCESSORIES 


149 


AwTlSYPHONAGE 
PlPE. 


is  a  mixture  of  red  and  white  lead,  linseed  oil,  and  a  little 
hemp. 

A  special  form  of  connection  is  given  at  B,  Fig.  99,  where 
the  lead  antisiphonage  pipe  is  attached  with  a  wiped  joint  to 
a  brass  union,  which  in  turn  is  connected  with  the  pottery 
ventilating  horn  ;  these  union  connections  usually  have  their 
faces  ground  together  to  enable  the  joints  to  be  readily  made 
and  disconnected.  There  are  many  places,  however,  where  a 
joint  like  B,  Fig.  99,  would  be  difficult  to  make  on  account  of 
the  space  they  occupy ;  but  where  an  antisiphonage  pipe  may 
pass  directly  through  a  wall  at  the  back  of  a  w.c.  such  a 
joint  could  easily  be  used. 

Another  antisi-  W.C.  OUTLET 

phonage  pipe  con- 
nection is  illustrated 
in  Fig.  100.  Here 
it  is  formed  in  the 
brass  socket  to 
which  the  outgo  of 
the  w.c.  is  joined. 
This  latter  arrange- 
ment, of  course,  can 
only  be  adopted 
where  the  pottery 
outgo  terminates 
well  above  the  floor. 

Where  practicable  one  of  the  best  methods  of  dealing 
with  an  antisiphonage  pipe  is  to  join  it  directly  to  a  lead  or 
iron  branch  instead  of  to  the  earthenware  outgo  of  a  w.c. 

Flush  Pipe  Connections. — Although  many  methods  have 
been  devised  for  connecting  a  flush  pipe  to  a  w.c.,  a  strong 
rubber  cone  will  generally  be  found  to  be  satisfactory  where 
a  horizontal  joint  is  required.  Eubber  cones  are  comparatively 
cheap,  and  permit  of  reliable  connections  being  made  in  con- 
fined situations,  whilst  many  patented  connections  take  up 
too  much  space.  Thin  rubber  cones  should  not  be  used,  as 
they  are  weak  and  are  soon  destroyed. 

Where  the  inlet  to  a  flushing  rim  is  in  a  vertical  position, 
a  good  joint  may  be  made  by  first  inserting  into  the  annular 


PIPE. 


FIG.  100.  —  Connection  between  \v.e.  and  lead 
pipe  beneath  floor. 


150      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

space  between  the  flush  pipe  and  socket  a  little  hemp,  and 
afterwards  filling  the  remaining  space  with  a  mixture  of 
molten  resin  and  tallow ;  a  little  brickdust  may  also  be  added 
to  increase  the  soundness  of  the  joint.  Molten  sulphur  also 
makes  a  good  joint. 

Flushing  Cisterns  for  W.C.'s — The  object  of  a  flushing 
cistern  is  not  only  to  regulate  the  volume  of  water  used  per 
flush,  but  also  to  reduce  to  a  minimum  the  risk  of  polluting 
the  water  supply,  by  avoiding  a  direct  connection  between 
the  water  service  pipe  and  a  w.c.  Flushing  cisterns  are 
also  designed  to  prevent  waste  of  water. 

There  are  many  kinds  of  flushing  cistern's,  but  they  may 


FIG.  101. — Nicholl's  and  Clarke's  double  valve  flushing  cistern. 

be  divided  into  the  following  orders:  (1)  Single  valve 
cisterns ;  (2)  Double  valve  cisterns ;  (3)  Valve  and  siphon 
cisterns ;  and  (4)  Waste  preventing  siphon  cisterns. 

The  first  and  second  classes  of  flushing  cisterns  are  not 
often  fixed  at  the  present  time,  as  they  are  rapidly  being 
displaced  by  those  of  the  third  and  fourth  classes.  It  is 
generally  recognised  that  only  siphon  types  of  flushing  cisterns 
should  be  used,  in  order  that  the  full  flush  of  water  may  be 
utilised  to  cleanse  a  w.c. 

Double  valve  cisterns  are  divided  into  two  compartments, 
and  have  a  valve  in  each.  The  compartment  in  which  the 
larger  valve  is  located  contains  the  regulation  flush,  and  the 
valves  are  so  arranged  that  when  one  is  closed  the  other  will 


SANITARY    FITTINGS    AND    ACCESSORIES 


151 


remain  open.     The  general  arrangement  of  these  cisterns  is 
clearly  shown  in  Fig.  101. 

A  valve  and  siphon  cistern  is  given  in  Fig.  102,  but 
unless  the  lever  is  let  go  after  the  discharge  has  started  the 
cistern  will  not  be  wholly  emptied  of  its  contents. 

Occasionally  it  will  be  found  that  when  water  flows  freely 
into  a  flushing  cistern  the  siphonic  action  is  not  properly 
broken  at  the  end  of  the  flush,  but  that  continuous  siphonage 
occurs,  the  water  being  withdrawn  from  the  cistern  as  quickly 
as  it  enters  it.  To  effectively  break  siphonic  action  it  is 
essential  that  air  enters  the  siphon  at  the  end  of  each 
discharge. 

In  the  siphon  shown,  Fig.  102,  a  small  hole  is  made  at 
the  top  of  the  dome, 
just  sufficient  in  size  to 
stop  siphonage  at  the 
end  of  the  flush,  but  not 
large  enough  to  interfere 
with  the  effective  work- 
ing of  the  siphon.  When 
the  dome  of  a  siphon 
is  of  iron  there  is  always 


FIG.  102.— Siphon  flushing  cistern. 


the  possibility  of  a  small 

aperture  getting  choked 

with   rust,  and   causing  the  siphon  to  be  somewhat   erratic 

in  its  action.     This  may,  however,  be  obviated    to   a  great 

extent  by  drilling  a  hole  in  the  iron  dome  and  inserting  a 

small  brass  plug  which  has  previously  been  pierced. 

The  form  of  cistern  Fig.  102  is  not  what  can  be  termed 
a  waste  preventer  in  the  strict  sense  of  the  term,  but  it  is 
nevertheless  a  fairly  good  type  of  cistern,  and  will  satisfy  the 
requirements  of  many  Water  Companies. 

A  real  waste-preventing  cistern  is  one  which  is  so  de- 
signed that  water  cannot  continuously  escape  through  a  flush 
pipe  when  resorting  to  irregular  practices  such  as  fastening 
down  the  cistern  pull,  or  by  holding  the  outlet  valve  clear 
of  its  seating,  by  putting  some  material  beneath,  or  by  the 
total  removal  of  a  valve. 

Waste-preventing    siphon    cisterns    are    made    in    many 


152     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


forms,  but  they  depend  principally  for  their  action  upon 
the  mechanical  displacement  of  a  volume  of  water  into  the 
outlet  limb  of  the  siphons,  or  upon  a  pneumatic  action.  The 
pneumatic  class  possesses  the  merit  of  dispensing  with  rods 
and  chains,  and  permits  of  their  contents  being  discharged  by 
the  simple  pressing  of  a  button  or  a  small  piston,  etc. 

Fig.  103  shows  a  displacer  type  of  siphon  waste- 
preventer,  and  its  action  is  as  follows :  When  the  lever 
is  pulled  down  the  piston  moves  up  the  cylinder, 
displaces  the  water  above  it  over  the  top  of  the  siphon 
bend,  and  charges  the  vertical  limb,  when  siphonage  is 
established.  It  will  be  observed  that  the  outlet  limb  of 

the  siphon  is  reduced  in 
diameter,  instead  of  being 
made  with  a  uniform  bore  ; 
some  form  of  contraction 
or  enlargement  should 
always  be  introduced  into 
such  siphons,  as  it  has  the 
effect  of  momentarily  re- 
tarding the  outflow  of 
water  at  the  commence- 
ment of  the  discharge, 
enabling  the  siphon  to  be 
better  charged,  and  of 

making  it  more  reliable  in  action.  Because  the  rod  of  the 
piston  in  Fig.  103  passes  through  the  top  of  the  dome,  no 
special  air-hole  is  essential  to  break  siphonage  at  the  end  of 
a  discharge,  as  a'ir  will  enter  the  siphon  at  the  side  of  the 
rod,  which  is  not  perfect  fitting  where  it  passes  through  the 
dome. 

A  waste-preventer  with  pneumatic  action  is  illustrated  in 
Fig.  104.  As  the  cistern  fills,  air  is  confined  at  the  top  of 
the  chamber  C.  At  the  bottom  of  the  siphon  a  disc  valve 
V  is  provided,  which  opens  on  a  hinge  during  the  discharge 
from  the  cistern,  but  falls  back  upon  its  seating  after- 
wards. A  small  pipe  is  joined  to  chamber  C,  and  the  other 
end  of  the  pipe  is  connected  with  the  small  bellows  B. 
When  the  cistern  is  filled  to  the  water-line,  siphonage  is 


FIG.  103.— AYaste  preventer  (Donltons' 
"Speedwell  ").  Overflow  and  ball- 
cock  omitted. 


SANITARY    FITTINGS    AND    ACCESSORIES 


153. 


established  by  pushing  the  knob  K  inwards  in  order  to 
compress  the  confined  air  in  chamber  C.  The  effect  of  this 
further  compression  is  to  dislodge  sufficient  water  over  the 
outlet  limb  of  the  siphon  and  to  bring  about  the  discharge. 

Flushing  cisterns  are  made  in  cast  iron,  wood  with  metal 
linings,  and  in  pottery  ware.  Iron  flushing  cisterns,  unless 
protected  with  a  glass  enamel,  or  other  suitable  coating,  are 
rapidly  corroded  with  many  soft  waters,  and  the  closets  are 
also  discoloured  with  rust.  Lead-lined  or  copper-lined 
cisterns  are  more  satisfactory  for  soft  waters,  the  latter 
being  the  more  durable  of 
the  two.  Lead,  however,  has 
the  advantage  of  being  a 
little  cheaper  than  copper. 
Pottery  cisterns  present  a 
clean  appearance,  and  are 
durable ;  they  are  more 
costly,  however,  than  some 
of  the  other  forms,  and  their 
use  is  limited  in  conse- 
quence. To  prevent  flushing 
cisterns  being  damaged  by 
frost  they  should  have  slop- 
ing sides. 

Lavatories. — The  chief 
point  of  construction  which 
requires  consideration  in 
connection  with  modern 

lavatories  is  the  arrangement  of  their  overflows.  Defects  which 
were  common  in  the  earlier  types  of  lavatories,  such  as  small 
waste  outlets,  and  soap  dishes  which  discharged  into  overflows, 
or  into  traps  beneath,  are  mostly  absent  in  modern  lavatories. 
These,  like  other  sanitary  fittings,  should  be  free  from  wood 
enclosures,  and  be  constructed  so  as  not  to  accumulate  filth. 
Porcelain  and  enamelled  fireclay  are  chiefly  used  in  this 
country  in  the  manufacture  of  lavatories,  the  latter  material 
being  used  where  specially  strong  and  durable  fittings  are 
required. 

A  good  shape  of  lavatory  is  the  oblong  form  with  straight 


Fro.  104. — Adams  pneumatic  action  waste 
preventer.  Ball-cock  and  overflow 
omitted. 


.154     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

front  and  circular  back,  the  latter  having  a  suitable  recess 
in  which  the  waste  outlet  may  be  located.  All  lavatories, 
whether  in  cheap  or  in  expensive  forms,  should  be  provided 
with  skirtings,  to  prevent  water  overflowing  and  trickling 
down  between  walls  and  the  backs  of  lavatories. 

The  tip-up  form  of  lavatory,  once  largely  used,  is  super- 
seded by  simpler  forms  which  are  more  readily  cleansed. 
Tip-up  basins  possess  an  advantage  in  having  a  quick  dis- 
charge, but  their  drawbacks,  such  as  the  fouling  of  the 
receivers,  the  disagreeable  odours  emitted  by  them  when  not 
regularly  cleansed,  and  the  wear  and  tear  upon  the  trunnions, 
overshadow  any  merit  they  possess. 

A  weakness  which  is  common  to  many  present  day 
lavatories  is  the  form  the  overflow  takes.  Overflows  should 
be  constructed  in  a  manner  which  will  admit  of  their  being 
easily  cleansed,  be  open  to  view,  and  be  of  a  good  size. 
Hidden  overflows  are  liable  to  get  their  surfaces  covered  with 
slimy  matter,  which  dries  and  emits  that  stuffy  smell  which 
is  peculiar  to  apartments  in  which  defective  sanitary  fittings 
are  placed ;  they  also  form  suitable  places  in  which  disease 
germs  may  rapidly  multiply. 

In  hospitals,  schools,  and  other  public  institutions,  it  is  of 
special  importance  that  sanitary  fittings  have  no  hidden  parts 
which  may  cause  the  dissemination  of  disease. 

In  Fig.  105  two  good  forms  of  overflows  are  shown. 
That  at  A  is  formed  within  the  basin,  and  made  open  as 
shown ;  it  is  readily  accessible,  and  is  easily  cleansed  by 
pushing  a  brush  through  it.  The  opening  above  the  weir  of 
the  overflow  may  be  covered  by  a  thin  metallic  hinged  flap  if 
desired.  At  B,  Fig.  105,  an  exposed  standing  waste  is  shown, 
which  serves  the  purposes  of  overflow  as  well.  This  standing 
waste  consists  of  a  short  metallic  tube  which  admits  of  easy 
removal  for  cleansing.  Porcelain  tubes  are  also  used  for 
wastes,  and  present  a  clean  appearance,  but  they  possess  the 
drawback  of  being  easily  broken. 

Concealed  standing  wastes  should  not  be  used,  even  if 
they  are  made  in  a  manner  to  admit  of  easy  removal,  for 
hidden  surfaces,  no  matter  how  accessible,  are  not  cleansed 
so  regularly  as  those  which  are  exposed  to  view. 


SANITARY    FITTINGS    AND   ACCESSORIES 


155 


C  and  D,  Fig.  106,  give  two  defective  forms  of  overflows ; 
neither  admits  of  easy  cleansing,  but  owing  to  its  shortness 
the  one  at  C  is  the  better  of  the  two. 


FIG.  105. — Good  forms  of  overflows. 


Iii  public  buildings,  lavatories  and  similar  fittings  are 
often  fitted  with  combination  hot  and  cold  water  valves,  but 
many  of  these  appliances  are  more  trouble  than  they  are 


FIG.  106. — Defective  forms  of  overflows. 

worth.  Combination  cocks  are  frequently  erratic  in  action 
and  troublesome  to  repair.  Separate  hot  and  cold  water 
cocks  are,  as  a  rule,  the  best  fittings  for  lavatories  and  similar 
appliances,  as  they  are  cheaper,  more  durable,  more  easily 


156     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

repaired,  and  the  temperature  and  volume  of  the  outflowing 
water  are  easily  adjusted. 

When  lavatories  are  fixed  with  standing  wastes,  care 
should  be  taken  to  leave  them  in  good  working  order. 
Occasionally  it  will  be  found  that  standing  wastes  when 
delivered  from  the  works  stick  a  little,  and  although  the 
defect  is  easy  to  remedy,  trouble  has  frequently  resulted 
through  neglecting  it. 

When  loose  plugs  are  used  for  lavatories,  they  should  be 
made  of  some  material  which  is  incapable  of  chipping  the 
glaze.  Loose  plugs  and  chains  give  very  little  trouble  under 
ordinary  circumstances,  and  they  are  simple  and  cheap. 

Brass  rods  occasionally  take  the  place  of  chains,  to  give 
a  smarter  appearance  and  to  make  a  stronger  fixing,  but  if 
the  guides  are  fairly  close  fitting  the  rods  are  liable  to  stick 
unless  some  lubricant  is  occasionally  applied.  On  the  other 
hand,  if  the  plugs  drop  freely  upon  their  seatings,  there  may 
be  danger  of  partially  unsealing  the  traps,  due  to  the  sudden 
compression  of  the  air  at  their  inlets.  This,  however,  applies 
more  specially  to  baths  than  to  lavatories,  as  the  overflows 
of  the  latter  would  often  afford  relief  for  the  air. 

For  supporting  lavatories  painted  cast  iron  or  porcelain 
enamelled  brackets  and  frames  are  very  serviceable,  and 
present  surfaces  which  will  only  collect  the  minimum  of 
dust.  Where  more  ornamental  fixings  are  required  various 
designs  of  friezes  and  standards  may  be  used. 

Ranges  of  Lavatories  for  offices,  schools,  hotels,  works, 
and  for  other  buildings,  may  readily  be  formed  with  separate 
lavatories,  or  with  those  with  overlapping  joints  as  in  Fig. 
107.  In  the  range  given  each  lavatory  is  provided  with  a 
different  but  good  form  of  overflow. 

A  more  elaborate  range  of  lavatories  by  Doultons  is 
shown  in  Fig.  108. 

Baths. — A  number  of  the  conditions  which  must  be 
satisfied  to  produce  a  good  type  of  bath  are  similar  to  those 
necessary  in  an  up-to-date  lavatory.  Baths  vary  in  size  and 
shape,  are  made  of  different  materials,  have  several  grades 
of  finish,  and  differ  in  the  kind  and  arrangement  of  their 
fittings. 


SANITARY   FITTINGS   AND   ACCESSORIES  157 

The  principal  materials  from  which  baths  are  made  are 
cast  iron  and  fireclay ;  each  material  has  its  special  merits 
according  to  the  class  of  building  for  which  a  bath  is 
required. 

The  degree  of  perfection  attained  in  the  manufacture  of 
cast-iron  baths  has  done  much  to  bring  these  fittings  into 
general  use,  and  the}7  are  produced  in  both  cheap  and  ex- 
pensive forms,  suitable  for  either  a  cottage  or  mansion. 

For  most  buildings  cast-iron  baths  with  roll  edges  are 
the  most  satisfactory  kind.  Iron  is  quickly  heated  when 
in  contact  with  hot  water,  and  the  rolled  edges  dispense  with 
the  use  of  wood  casings. 

To  protect  iron  baths  from  rust,  and    to    give   them  a 


FIG.  107. — Range  of  lavatories  with  overlapping  joints,  by  Twy fords  Ltd. 

smooth  and  satisfactory  finish,  their  inner  surfaces  are 
enamelled,  whilst  their  outer  surfaces  are  more  generally 
painted. 

Metallic,  vitreous,  and  porcelain  enamels  are  used,  and 
the  grade  of  a  bath  is  regulated  by  the  kind  of  enamel 
used. 

Metallic  enamel  is  only  the  application  of  paint,  which 
is  fixed  at  a  moderately  high  temperature,  the  number  of 
coats  regulating  the  finish  desired. 

Vitreous  and  porcelain  enamels  produce  a  smooth,  glassy 
surface,  which  resembles  that  of  glazed  earthenware. 

Glazed  fireclay  baths  are  very  durable,  and  their 
surfaces  are  easily  cleansed ;  these  baths  are  specially  suited 


158     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

for  public   and  other  institutions,  where  they  are  often   in 
demand,  and  where  substantial  fittings  are  essential. 

For  private  houses,  however,  fireclay  baths  when  only 
occasionally  used  are  not  suitable ;  they  are  too  heavy  and 
cumbersome,  absorb  too  much  heat  from  the  water,  take  a 
long  time  to  heat  through,  and  unless  filled  for  a  time  lief  ore 


FIG.  108. — Lavatory  range  by  Doultons  Ltd. 

they  are  actually  required  their  surfaces  strike  cold  to  the 
bather,  especially  in  winter  time. 

Other  materials,  such  as  copper,  tinned  steel,  and 
enamelled  sheet  iron,  are  used  to  a  limited  extent  in  the 
manufacture  of  baths,  and  these  materials  have  the  advantage 
of  lightness  and  are  suitable  for  special  purposes. 

For  portable  baths  in  hospitals  and  in  other  establish- 
ments, copper  is  a  very  satisfactory  material,  as  it  is  a 


SANITARY   FITTINGS    AND   ACCESSORIES 


159 


good  conductor  of  heat,  and  readily  acquires  a  temperature 
which  only  differs  a  little  from  that  of  the  water  inside. 
On  account  of  the  expense  of  copper  the  cheaper  materials 
named  are  frequently  used  where  cost  is  the  chief  con- 
sideration. Portable  baths  for  hospitals  are  frequently  fixed 
on  rubber-tyred  wheels,  provision  being  made  in  the  corridors 
for  either  filling  them  with  water  or  for  effecting  their 
discharge. 

Overflows  and  waste  outlets  of  baths  should  be  of  simple 


FIG.  109. — Standing  overflow  and  waste  outlet. 


construction,  and  the  traps  should  be  fixed  immediately 
beneath  the  outlets. 

Fig.  109  shows  a  good  form  of  standing  waste  and 
overflow,  and  the  correct  position  for  the  trap,  which  may 
be  either  of  brass,  or  of  cast  iron  and  glass  enamelled  inside. 
When  standing  wastes  are  used,  recesses  are  necessary  in 
the  ends  of  the  baths  to  enable  the  wastes  to  be  located  out 
of  the  way  of  the  bather's  feet. 

A  form  of  waste  which  is  often  used  for  expensive  baths 
is  given  in  Fig.  110.  These  wastes  present  a  nice  appear- 


160     DOMESTIC    SANITARY    ENGINEERING    AND   PLUMBING 


ance  when  well  polished  or  silver  plated,  but  they  are  very 
objectionable  from  a  sanitary  standpoint,  as  they  contain 
surfaces  upon  which  filth  is  liable  to  gather  and  to  remain 
unobserved. 

It  will  be  noticed  from  the  construction  of  the  waste 
that  water  will  rise  in  the  annular  space  between  the  tubes 
when  a  bath  is  filled,  and  in  consequence  soapy  matter  will 
be  deposited  upon  the  surfaces  when  the  bath  is  in  use. 

Some  Water  Companies,  however,  do  not  allow  overflows 
of  baths  to  discharge  into  their  waste  pipes,  but  require 

them  to  be  arranged 
as  in  Fig.  111. 
To  the  outlet  a 
length  of  pipe  is 
attached,  and  the 
other  end  of  the 
pipe  terminates  in 
the  open  air,  so  as 
to  serve  the  pur- 
pose of  a  warning 
pipe.  This  form  of 
overflow  was  intro- 
duced with  a  view 
to  minimise  waste 
of  water,  but  its 
value  for  that 
purpose  is  very 
questionable.  It  is,  however,  a  very  defective  form  of  over- 
flow, as  it  does  not  permit  of  being  cleansed,  and  it  allows 
cold  air  to  flow  into  the  bathroom,  along  with  any  fine 
particles  of  matter  which  have  been  deposited  on  the  surfaces 
of  the  pipe. 

For  hospitals  and  other  places  where  it  is  desirable  to 
have  special  facilities  for  cleansing  the  floors  and  walls  of 
bathrooms,  baths  may  be  obtained  which  revolve  round  their 
waste  outlets.  This  arrangement  is  specially  useful  where 
space  is  limited,  as  a  bath  when  in  use  may  be  turned  from 
the  wall  of  an  apartment  so  as  to  allow  an  attendant  to  get 
on  either  side. 


FIG.  110. — Defective  form  of  standing  overflow, 


SANITARY    FITTINGS    AND    ACCESSORIES  161 

Sinks. — The  uses  of  sinks  are  varied,  and  different 
materials  are  used  in  their  formation.  Well  glazed  fireclay 
sinks  are  specially  suited  for  small  houses,  and  they  may 
be  obtained  in  inexpensive  forms.  For  mansions,  hotels, 
restaurants,  and  public  institutions,  glazed  fireclay  is  the 
most  suitable  material  for  sinks  for  general  purposes,  and 
for  vegetable  sinks.  A  softer  material,  however,  is  often 
necessary  for  sinks  which  are  used  for  washing  glass  and 
china  ware,  in  order  to  minimise  the  risk  of  chipping  these 
goods.  Where  a  moderate  amount  of  care  is  exercised,  and 
where  sinks  are  fairly  deep  and  wood  drainers  are  used, 
fireclay  sinks  are  often  suitable  for  cleansing  china  ware, 
but  for  large  buildings  it  is 
usually  desirable  to  provide 
special  sinks  for  this  purpose. 
Hard  wood,  such  as  teak,  and 
also  softer  woods  when  the 
latter  are  protected  with  soft 
metal  linings,  make  good  sinks 
for  washing  crockery  ware. 
Metal-lined  sinks  are  superior 
to  those  made  entirely  of  wood, 
for  after  a  time  decay  sets 
in,  and  the  wood  becomes  FIG.  ill.— Tell-tale  overflow, 
saturated  with  greasy  water, 

and  during  the  partial  drying  of  the  wood  offensive  odours 
are  also  emitted. 

Where  sinks  are  used  that  are  lined  with  either  block 
tin  or  lead,  their  sides  should  be  tapered  to  allow  the 
linings  to  slide  a  little  inside  the  wood  casings  when  the 
metal  expands  and  contracts.  Sinks  with  vertical  sides 
rigidly  hold  soft  metal  linings,  and  cause  the  latter  to  buckle 
and  crack  when  alternately  heated  and  cooled. 

Fig.  112  shows  a  wood  sink,  and  a  suitable  method  of 
lining  it  with  either  tin  or  lead.  The  metal,  it  will  be  observed, 
is  not  turned  over  and  nailed  down  on  the  top  edges  of  the 
sink,  but  is  trimmed  off  a  little  below  the  top  edge,  and 
held  by  means  of  an  oak  capping  piece  which  covers  the 
free  edge  of  the  lead.  When  a  wood  sink  is  treated  in  this 
n 


162     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

manner  either  lead  or  tin  linings  will  move  a  little  and  have 
a  much  longer  life. 

Butler's  sinks  are  frequently  made  of  tinned  copper,  and 
are  oval  in  shape ;  or  larger  sinks  may  be  of  wood  and  be 
lined  with  tin. 

Drainers  for  sinks  when  made  of  teak  are  durable,  but 
when  soft  woods  are  used  they  should  be  covered  With  either 
block  tin  or  lead,  the  former  metal,  of  course,  being  the 
better  of  the  two. 

Either  lead  or  tin  is  readily  worked  into  the  grooves 
of  a  drainer  after  it  is  first  heated  to  about  200°  F.  either 
by  boiling  water  or  by  other  means.  The  metal  should 
be  rubbed  into  the  grooves,  as  any  attempt  to  drive  it  in 

will  result  in  the  metal  straight- 

_  .        ,    ? 

ening  out  from  one,  as  it  is  driven 
in  another  groove. 

With  regard  to  overflows, 
these  should  not  be  formed  in 
sinks  from  which  greasy  matter 
is  discharged,  unless  damage  is 
likely  to  be  caused  should  they 
overflow.  In  many  sinks  over- 

flows  are  obJecti™able  and  are 

not  required. 

Cast-iron  sinks,  either  plain  or  enamelled,  are  also  made, 
but  the  former  have  a  dirty  appearance,  and  the  latter 
although  cheaper  than  those  of  fireclay  are  less  durable. 

Wash-Tubs. — These  fittings  require  very  little  comment- 
ing upon,  as  they  resemble  sinks  excepting  that  they  are 
deeper  and  have  their  fronts  formed  with  a  good  slope. 
The  most  suitable  material  for  wash-tubs  is  enamelled 
fireclay.  Overflows  to  these  fittings  are  unnecessary,  and 
only  a  simple  form  of  waste  outlet  is  required.  On  account 
of  the  weight  of  fireclay  tubs  pedestals  of  the  same  material 
make  the  best  forms  of  supports. 

Slop  Sinks. — In  construction  slop  sinks  are  similar  to 
water-closets,  and  their  outlets  should  be  readily  accessible, 
and  permit  of  a  simple  and  effective  joint  being  made  with 
the  branch  waste  pipes.  A  good  form  of  slop  sink  is  given 


SANITARY    FITTINGS    AND    ACCESSORIES 


1G3 


in  Fig.  113.  In  the  basin  either  a  brass  or  galvanised  iron 
hinged  grate  is  provided,  upon  which  a  pail  can  be  placed. 
Hot  and  cold  draw-off  taps  are  often  fixed  immediately 
above  the  sink  to  enable  water  to  be  obtained  for  cleansing 
purposes.  An  overhead  flushing  cistern  is  essential  for  slop 
sinks,  so  as  to  cleanse  them  after  receiving  a  pailful  of  slops. 

For  hospital  use  special  forms  of  slop  sinks  are  necessary, 
as  provision  must  be  made  for  flushing  out  bed  pans,  etc. 

Urinals. — During  the  last  few  years  great  strides  have 
been  made  in  the  design  and  construction  of  urinals,  and 
many  defects  which 
were  common  in  the 
earlier  types  are  mostly 
eliminated  in  the  best 
modern  fittings. 

The  urinal  is  the 
most  difficult  of  sani- 
tary fittings  to  keep  in 
a  satisfactory  state  of 
cleanliness,  and  more 
especially  when  cum- 
bersome and  useless 
pieces  of  pottery  are 
utilised  in  their  con- 
struction. 

All  urinals  require 
a  liberal  amount  of 


FIG.  113. — Slop  hopper. 


Hushing  with  clean  water,  as  urea  from  the  urine  is  readily 
decomposed,  and  gives  off  the  well-known  ammouiacal  odours 
which  are  common  in  badly  flushed  and  poorly  constructed 
urinals. 

In  private  houses  a  w.c.'  serves  the  purpose  of  a  urinal, 
but  for  works,  clubs,  hotels,  schools,  and  many  other 
buildings,  as  well  as  in  public  thoroughfares,  separate  urinals 
are  a  necessity. 

Urinals  commonly  take  the  form  of  lipped  earthenware 
basins,  of  enamelled  iron  and  fireclay  troughs,  and  of  slate 
and  fireclay  stalls.  Well  glazed  and  constructed  fireclay 
stalls  make  the  best  types  of  urinals,  but  these  are  usually 


164     DOMESTIC    SANITARY    ENGINEERING   AND    PLUMBING 


more  costly  than  other  forms,  excepting  those  where  marble 
enters  into  their  construction. 

From  a  theoretical  standpoint,  trough  urinals  when 
arranged  to  stand  nearly  full  of  water  make  good  forms 
provided  they  are  properly  used  and  flushed,  as  the  urine  is 
diluted  with  a  large  volume  of  water.  Trough  urinals,  how- 
ever, are  often  subjected  to  improper  use,  and  they  soon  become 

offensive,  owing  to  large  surfaces 
which  are  wetted  with  urine  and 
which  receive  no  flushing  water. 

Stall  urinals  which  are  formed 
of  slate  slabs  do  not  admit  of 
the  whole  of  their  surfaces  being 
cleansed,  and  therefore  this  type 
is  not  suitable  for  installing  inside 
buildings  or  in  confined  situa- 
tions. If,  however,  for  economical 
considerations,  slab  urinals  are 
adopted  where  they  can  be  exposed 
to  the  external  air,  the  division 
slabs  should  terminate  about  18 
inches  clear  of  the  channels  in  the 
floors,  and  be  supported  at  the 
front  by  means  of  galvanised  iron 
columns  as  shown  in  Fig.  114. 
The  floor  channels  should  be  of 
glazed  earthenware  with  an  outlet 
at  one  end,  or  in  the  case  of  a 
long  range  the  outlet  may  be 
better  located  near  the  centre. 

Slab  urinals,  Fig.  114,  may  either  be  of  slate  or  glazed 
fireclay,  the  former  being  the  cheaper  of  the  two,  but  the 
latter  can  be  more  readily  cleansed. 

The  chief  points  to  consider  when  selecting  semi-circular 
or  radial  back  urinals  are : — 

1.  That  they  are  constructed  in  well  glazed  fireclay  or 

similar  ware. 

2.  That  they  are  made  in  as  few  pieces  as  practicable, 

to  limit  the  number  of  joints. 


FIG.  114. — Form  of  slab  urinal. 


SANITARY    FITTINGS    AND    ACCESSORIES 


165 


3.  That  they  contain  the  minimum  length  of  channel. 

4.  That  all  surfaces  which  are  liable  to  be  wetted  with 

urine  are  effectively  flushed. 

5.  That  the  minimum  number  of  traps  be  used. 


FIG.  115. — Twyford's  urinal  range  in  glazed  fireclay. 

G.  That  the  joints  are  well  formed,  and  that  the 
minimum  length  of  joints  come  in  contact  with 
urine. 

7.  That  no  part  of  a  channel  be  difficult  to  cleanse  or 

be  partially  obscured  from  view. 

8.  That    suitable    flushing    apparatus,   together    with    a 

liberal  supply  of  water,  be  provided. 
Single    stall    urinals,  provided    that    they    are    of    good 


166     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

design,  present  very  little  difficulty,  as  they  can  be  formed 
in  one  piece  of  fireclay ;  but  when  ranges  of  urinals  are 
formed,  joints  become  imperative,  and  the  effective  discharge 
of  the  urine  from  the  stalls  becomes  a  more  difficult  matter. 

Joints  in  channels  of  range  urinals  are  frequently  a 
source  of  weakness,  and  in  order  to  overcome  this  defect 
each  stall  is  occasionally  provided  with  a  separate  outlet 
and  trap.  Traps,  however,  when  numerous  are  objectionable, 
owing  to  the  volume  of  urine  they  hold,  and  the  connections 
between  the  channels  and  traps  are  frequently  of  defective 
design. 

In  order  that  one  trap  may  suffice  for  one  or  more 
ranges  of  urinals,  main  channels  can  be  arranged  along  the 
front  of  the  stalls,  and  covered  with  movable  iron  or  brass 
gratings ;  a  small  branch  or  subsidiary  channel  from  each 
stall  joins  with  the  main  channels,  and  the  whole  of  the 
channels  are  made  to  fall  to  a  common  outlet  where  a  trap 
is  provided.  The  chief  drawback  of  this  arrangement  is  the 
length  of  channel  required,  and  unless  the  whole  of  the 
grates  and  channels  are  frequently  cleansed  by  an  attendant 
they  are  liable  to  get  in  a  very  unsatisfactory  state, 

A  good  form  of  urinal  is  shown  by  Fig.  115,  where  an 
open,  continuous  channel  is  made  in  the  urinal  itself,  and 
where  the  base  of  the  division  facings  terminates  clear  of  the 
channel. 

Inlets  to  traps  should  be  covered  with  a  domical  grating 
to  avoid,  as  far  as  practicable,  the  accumulations  of  burnt 
matches  and  other  matters  from  choking  up  the  grating  and 
causing  the  floor  of  a  urinal  apartment  to  be  flooded. 


CHAPTER    Vll 
SOIL   AND   WASTE    PIPES 

Soil  Pipes. — Although  from  a  legal  point  there  sometimes 
appears  a  little  difficulty  in  interpreting  the  term  "soil 
pipe,"  the  ordinary  individual  generally  understands  it  to 
mean  a  pipe  or  channel  above  the  level  of  the  ground, 
communicating  with  one  or  more  water-closets  and  a  drain ; 
the  purpose  of  a  soil  pipe  being  to '  convey  discharges  from 
w.c.'s  to  a  drain. 

Materials. — The  materials  of  which  soil  pipes  are  made 
are  lead,  cast  iron,  and  occasionally  copper.  Solid  drawn 
lead  pipes  have  many  advantages  as  soil  pipes;  they  are 
very  durable  when  properly  fixed,  have  smooth  surfaces 
which  when  properly  flushed  are  easily  cleansed ;  they  can 
be  securely  jointed,  can  be  fixed  in  long  lengths ;  are  easily 
bent  to  suit  various  situations,  and  contain  the  minimum 
number  of  joints. 

Lead  as  a  material  for  soil  pipes  also  has  drawbacks. 
One  of  the  disadvantages  of  lead  soil  pipes  is  their  higher 
initial  cost  when  compared  with  iron  pipes,  although  if  the 
durability  of  the  former,  and  their  intrinsic  value  as  old 
material,  were  taken  into  account,  lead  pipes  would  finally 
prove  the  cheaper  to  use.  Another  disadvantage  is  that 
lead  soil  pipes  are  liable  to  be  bent  and  disfigured  by 
expansion  if  exposed  to  the  direct  rays  of  the  sun.  This 
difficulty  can  be  overcome  by  protecting  them,  when  in 
exposed  situation,  with  iron  shields,  which  are  made  to 
represent  square  or  rectangular  iron  pipes,  but  the  extra 
cost  involved  would  often  be  prohibitive. 

To  prevent  lead  pipes  being  distorted  by  expansion, 
expansion  joints  are  occasionally  used,  but  the  form  of  joint 

167 


168     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

generally  adopted  for  these  pipes  is  not  reliable,  and  it  is  also 
troublesome  to  repair. 

Iron  Soil  Pipes  possess  the  advantages  of  being  self- 
supporting,  of  being  easily  fixed,  and  of  being  cheaper  than 
lead  pipes  at  the  outset.  The  surfaces  of  iron  pipes,  however, 
require  some  form  of  protective  coating  to  preserve  them 
from  rusting. 

Drawbacks  of  iron  soil  pipes  are :  they  are  not  so 
durable  and  smooth  as  those  of  lead,  special  bends  and  .other 
fittings  are  often  required,  the  interior  surfaces  of  the  pipes 
get  rough  owing  to  the  decay  of  the  protective  coatings,  and 
they  contain  comparatively  a  greater  number  of  joints. 

Copper  Soil  Pipes  are  too  expensive  for  general  work, 
but  where  their  surfaces  are  tinned,  and  these  pipes  are 
properly  jointed,  they  are  suitable  for  high  class  work  where 
lead  pipes  may  prove  unsatisfactory. 

It  is  no  unusual  occurrence  for  the  bottom  length  of  an 
unprotected  lead  soil  pipe  to  be  damaged  when  in  a  position 
where  it  can  be  kicked,  and  occasionally  a  length  of  iron 
pipe  is  used  at  the  bottom  of  a  stack  of  lead  pipes  when  the 
latter  are  likely  to  be  subjected  to  improper  usage. 

Thickness  of  Soil  Pipes. — The  walls  of  lead  soil  pipes 
should  not  be  thinner  than  7-lb.  lead,  and  for  good  work  a 
thickness  equal  to  that  of  8-lb.  lead  should  be  used.  The 
thickness  of  iron  soil  pipes  should  not  be  less  than  J  inch,  to 
enable  sockets  of  sufficient  strength  to  be  formed.  A  6  feet 
length  of  4  in.  xj-  in.  cast-iron  soil  pipe  should  weigh  not 
less  than  60  Ib. 

In  Great  Britain  it  is  the  usual  custom  where  practicable 
to  fix  soil  pipes  on  the  external  face  of  outside  walls. 
Although  this  practice  has  much  to  commend  it  under 
ordinary  circumstances,  such  positions  are  not  conducive  to 
the  best  results  so  far  as  the  ventilation  of  drains  is  con- 
cerned. Soil  pipes  when  fixed  inside  buildings  are  protected 
from  the  inclement  weather  of  winter,  and  they  may  be  made 
fairly  accessible.  On  account  of  the  protection  afforded 
inside  pipes  in  cold  weather  ventilation  is  active,  where  with 
pipes  in  external  positions  ventilation  would  be  practically 
stagnant.  Where  soil  pipes,  however,  are  fixed  inside 


SOIL    AND   WASTE   PIPES  169 

buildings  there  should  be  no  doubt  about  the  soundness  of 
the  work  or  of  the  quality  of  the  materials  used,  and  every 
precaution  should  be  taken  to  make  them  satisfactory  in 
every  respect. 

Soil  pipes  when  fixed  on  the  outer  surfaces  of  walls 
possess  the  advantages  of  being  exposed  to  view,  and  in  the 
case  of  a  defect  less  harm  is  likely  to  be  done  than  with  a 
defective  inside  pipe. 

Climatic  conditions  also  regulate  the  positions  of  soil  and 
waste  pipes.  In  countries  where  it  is  extremely  cold  in 
winter,  with  the  thermometer  sometimes  recording  zero  and 
below,  there  is  the  possibility  of  outside  pipes  getting  blocked 
with  ice.  . 

Arrangement  of  Soil  Pipes  and  their  branches.  The  chief 
points  to  consider  when  arranging  soil  pipes  are :  that  their 
branches  are  suitably  placed,  have  good  pitches  where  practic- 
able, and  that  reliable  connections  can  be  made ;  that 
antisiphonage  pipes  do  not  cross  the  soil  pipes  unless 
absolutely  necessary,  that  as  few  joints  as  possible  are  buried 
in  walls,  and  that  all  branches  which  join  a  soil  pipe  curve 
in  the  direction  of  the  flow. 

Fig.  116  shows  how  the  crossing  of  pipes  may  be  avoided 
where  the  water-closets  are  located  immediately  in  front  of 
windows,  by  fixing  the  main  soil  and  principal  antisiphonage 
pipes  on  different  sides  of  the  windows.  At  A,  Fig.  116,  all 
the  pipes  are  supposed  to  be  of  lead,  whilst  the  main  pipes 
and  junctions  in  B  are  of  iron,  with  lead  branches  passing 
through  the  walls  to  the  fittings. 

When  iron  pipes  are  used  rust  pockets  should  be  pro- 
vided on  the  antisiphonage  pipes,  with  means  of  access  to 
enable  accumulations  of  rust  to  be  readily  removed. 

It  often  occurs  that  a  straight  branch  between  a  soil 
pipe  and  w.c.  requires  to  be  fixed  as  Fig.  117,  and  although 
this  form  of  branch  presents  no  special  difficulty  when  lead 
soil  pipes  are  used,  the  use  of  iron  pipes  and  of  an  ordinary 
short  junction  causes  a  joint  to  come  in  the  wall.  Where 
the  work  is  properly  carried  out,  and  the  soil  pipes  are  period- 
ically tested,  joints  in  walls  are  not  so  objectionable,  but  for 
general  work  it  is  better  to  have  all  joints  where  they  can  be 


170     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


readily  seen  and  easy  of  access.  In  Fig.  117  a  special  iron 
junction  with  long  branch  is  shown,  together  with  an 
antisiphonage  pipe  connection  which  is  shown  a  little  on  one 
side  of  the  branch. 

Soil  pipes  should  always  discharge  directly  into  drains, 

i — rr 


A 


FIG.  116. — Lead  and  iron  soil  pipes. 

that  they  may  also  act  as  ventilating  pipes  for  the  drainage 
system.  The  upper  ends  of  soil  pipes  should  terminate  so  as 
to  be  well  removed  from  dormers,  chimneys,  and  other  places 
that  afford  direct  communication  with  the  interiors  of 
buildings. 

When  a  soil  pipe  comes  too  close  to  a  dormer  it  should 
be  carried  up  the  roof,  and  terminate  at  a  suitable  elevation 


SOIL    AND   WASTE    PIPES 


171 


above  the  dormer.  If  a  soil  pipe  should  terminate  near  the 
top  of  a  chimney,  drain  air  will  frequently  be  found  to  pass 
down  the  chimney  under  certain  atmospheric  conditions,  and 
when  no  lire  is  burning  in  the  grate.  It  is  therefore  obvious 
that  unless  soil  pipes  terminate  in  suitable  positions  that  the 
value  of  sound  joints,  good  materials,  and  special  forms  of 
connections  are  very  materially  nullified. 

In  large  buildings,  where  ranges  of  closets  are  fixed 
immediately  beneath  one  another,  and  where  long  branches 
are  required,  great  care  is  necessary  in  the  arrangement  of 
the  pipes.  A  number  of  single  closets  when  fixed  over  each 


FIG.  117.— Special  iron  junction. 

other  is  comparatively  simple  work,  but  when  ranges  of 
closets  are  required  on  various  floors  the  soil-pipe  work  is '  of 
a  more  complex  character,  and  both  thought  and  skill  are 
essential  to  plan  and  properly  execute  the  work. 

Plan  and  section  Fig.  118  show  the  arrangement  of  the 
soil  pipe  work  on  one  of  the  floors  of  a  large  building,  the 
fittings  being  omitted  in  order  to  make  the  connections  clear. 
The  main  soil  pipe  and  antisiphonage  pipe  are  fixed  on  the 
outside  face  of  a  wall,  whilst  the  long  branch  B  which 
intercepts  the  connections  from  the  closets  is  situated 
beneath  the  floor.  The  amount  of  pitch  for  branch  B  is 
limited  by  the  depth  of  the  floor  joints,  and  as  the  distance 


172     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


between  the  floor  and  top  of  the  branch  is  also  very  limited, 
the  short  branches  from  the  closets  should  be  in  the  form  of 


bends,  and  should  join  at  the  side  of  the  long  branch  B,  as 
shown  on  plan.  Assuming  the  long  branch  B,  Fig.  118,  is 
fixed  close  to  the  wall,  and  that  closets  with  back  outlets  are 


SOIL    AND    WASTE    PIPES 


173 


used,  the  short  branches  between  the  long  branch  and  the 
closets  would  be  nearly  straight,  and  would  practically  enter 
branch  B  at  right  angles.  Right-angled  connections  would 
of  course  cause  waste  matter  at  each  discharge  to  flow  in 
both  directions  in  the  horizontal  branch,  so  that  solid  matter 
would  often  lodge  on  the  higher  side,  until  it  was  removed 
by  a  discharge  from  another  fitting.  The  arrangement  in 
Fig.  118  allows  discharges  to  enter  the  main  channel  in  a 
manner  that  all  solid  matter  may  be  removed  at  each  flush. 
The  branch  antisiphonage  pipes  are  all  shown  connecting 
with  the  bends,  to  which  the  closets  are  also  directly  joined, 
as  this  method  allows  reliable  joints  to  be  made. 

To  facilitate 
the  fixing  of  the 
pipes,  and  to  per- 
mit of  the  greater 
portion  of  the  work 
being  executed  in 
the  workshop, 
flange  joints  may 
be  made  in  con- 
nection with  lead 
pipes  as  in  Fig. 
119,  which  shows 
enlarged  detailed 
connections  for  one 

w.c.  Lead  collars  should,  of  course,  be  slipped  over  the  ends 
of  the  pipes  before  the  latter  are  flanged  over  on  the  floor. 
To  prevent  distorting  any  of  the  pipes  by  opening  the  ends 
of  those  to  be  flanged,  the  latter  should  first  be  heated  with 
a  lamp  or  by  other  means.  If  an  ordinary  brass  socket  S, 
Fig.  119,  is  used  for  a  closet  connection,  it  may  require  a 
little  cutting  off  its  plain  end,  so  that  its  lower  edge  will 
stand  clear  of  the  lead  collar  on  the  floor  as  shown.  The 
sockets  when  treated  in  the  manner  described  allow  simple 
air-tight  joints  to  be  made,  besides  forming  suitable  fixings 
for  the  bends. 

It  will,  of  course,  be  understood  that  in  Fig.   118   the 
joists  are  assumed  to  run  in  the  right  direction,  thus  allowing 


FIG.  119. — Enlarged  detail  in  connection  with 
Fig.  118. 


174     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


the  long  branch  to  be  fixed  in  the  manner  shown.  If,  how- 
ever, the  pipes  cannot  be  fixed  beneath  a  floor  as  in  Fig.  118, 
either  a  raised  platform  would  be  required  or  closets  with  P 

traps  would  be  neces- 
sary. Even  assuming 
the  latter  plan  were 
adopted,  a  low  platform 
may  still  be  essential 

p" ^CI  to    give  the    necessary 

pitch  where  th  e 
branches  are  long. 

Much  time  is  saved 
in  this  class  of  work 
and  the  latter  is  much 
easier  to  carry  out  if 
full-sized  working  draw- 
ings are  made.  All  the 
bends  can  then  be  made 
to  correct  pitches, 
branch  joints  prepared, 
and  a  number  of  joints 
may  be  made  before  the 
pipes  are  placed  in 
position. 

Antisiphonage  Pipes. 
—Because  traps  are 
liable  under  certain  con- 
ditions to  have  their 
contents  siphoned  out, 
antisiphonage  pipes  are 
provided  to  preserve  the 
equilibrium  of  the  air 
pressure  on  the  inlet 
and  outlet  sides  of  traps, 
Joints  on  these  pipes  require  to  be  carefully  prepared  to 
enable  air  to  iiow  through  them  without  unnecessary  inter- 
ruption. When  a  soil  and  antisiphonage  pipe  are  fixed  on  a 
wall  fairly  close  together,  it  is  unimportant  whether  the  Anti- 
siphonage pipe  joins  the  soil  pipe  above  the  highest  branch, 


GBOUWD     Level-. 


Connections  of  antisiphonage  pipes 
ill. 


FIG.  120. 

with  bends  on  the  outside  face"  of  a  wal 


SOIL    AND    WASTE    PIPES 


175 


or  whether  it  is  continued  and  terminates  as  by  dotted  line 
in  Fig.  120. 

Instead  of  joining  antisiphonage  pipes  with  the  soil  pipe 
branches  in  the  w.c.  apartments,  they  are  frequently  connected 
to  the  bends  on  the  outside  face  of  a  wall  as  in  Fig.  120. 
This  method  of  dealing  with  the  antisiphonage  pipes  possesses 
the  advantage  of  simplifying  the  fixing  of  these  pipes,  but  it 
should  only  be  adopted  where  the  w.c.'s  are  fixed  immediately 
at  the  back  of  the  wall,  or  where  very  short  portions  of  the 
branches  are  left  without  direct  ventilation. 

The  bye-laws  of  the  London  County  Council  limit  the 
connection  of  an  antisiphonage  pipe  to  be  not  less  than 

3  inches  and  not  more  than 
12  inches  from  the  top  of  a 
trap,  so  the  arrangement  in 
Fig.    120    would   not   often 
satisfy  the  bye-laws  in  ques- 
tion.    Although  the  12-inch 
limit    may  be   sufficient   for 
many  cases,  there  are  many 
others    where    this    distance 
could  with  advantage   be   a 
little  increased.   Fur  example, 
take   a   case   like  Fig.   121, 
where  it  would  be  positively 
absurd  to  arrange  the  anti- 
siphonage pipe  to  join  the  branch  nearly  in  the  middle  of 
the  wall,  as  indicated   by  dotted  lines,  in   order  to   satisfy 
the     12-inch     limit,     when     a     few    inches     farther    away 
would  allow  the  joint  to  be  made  in  a  more  rational  place. 

Sizes  of  Soil  Pipes. — No  formula  is  necessary  to  calculate 
the  sizes  of  soil  pipes,  as  these  are  entirely  governed  by 
practical  considerations.  The  general  size  of  a  soil  pipe  is 

4  inches  diameter,  not  because  a  smaller  size  is  inadequate 
to  carry  away  the  discharges  from  a  number  of  w.c.'s  but 
because  this  size  makes  an  effective  outlet  ventilator  for  a 
drainage    system,  and  because    it  may  be  kept  in  a    fairly 
cleanly  state. 

Soil  pipes  of  3^   inches  diameter  are  better  than  those 


FIG.  121. — Lead  branch  and  anti- 
siphonage pipe. 


176     DOMESTIC    SANITARY    ENGINEERING   AND   PLUMBING 

of  a  larger  diameter  so  far  as  the  cleanliness  of  their  inner 
surfaces  is  concerned,  but  for  a  principal  outlet  ventilator  a 
3  J -inch  pipe  is  rather  small,  and  especially  when  there  is 
a  number  of  bends  in  the  stack.  When  a  stack  of  soil  pipes 
is  not  required  to  act  as  a  drain  ventilator,  smaller  sizes  of 
pipes  may  be  adopted ;  but  special  attention  must  be  devoted 
to  the  sizes  of  the  antisiphonage  pipes,  for  the  better  a  stack 
of  pipes  is  scoured  with  flushing  water,  the  more  readily  will 
traps  lose  their  seals,  unless  adequate  means  be  provided  to 
counteract  this. 

The  question  is  sometimes  asked,  how  many.w.c.'s  may  be 
discharged  into  a  stack  of  4-inch  pipes  without  causing  over- 
flow at  any  of  the  lower  fittings  ?  The  exact  number  would 
be  difficult  to  state,  as  it  depends  upon  a  variety  of  conditions, 
such  as  the  possible  number  of  w.c.'s  likely  to  be  flushed  at 
the  same  time,  the  type  of  closet  used,  the  amount  of  ob- 
struction offered  to  a  discharge  by  bends,  etc.,  in  the  pipes, 
and  also  upon  the  arrangement  of  the  pipes.  Thus  it  will 
be  clear  that  only  a  hypothetical  solution  can  be  arrived  at. 
The  time  taken  to  flush  a  wash-down  closet  through  a  1  J-inch 
flush  pipe  with  2J  gallons  of  water  is  roughly  estimated  at 
5  seconds,  and  if  the  area  of  the  IJ-inch  pipe  and  that  of 
the  4-inch  soil  pipe  are  compared,  the  latter  will  be  found 
to  be  rather  more  than  7  times  larger  than  the  former ;  thus 

42      4    4     2     2       1 
^  T2  =  T  X  T  X  ^  X  -  =  7~.      If  it  is  assumed  for  the  sake  of  sim- 

J-2          1        1        O        O  9 

plicity  that  liquid  matter  is  discharged  into  and  through  a  stack 
of  4-inch  soil  pipe  with  a  uniform  velocity,  then  seven  w.c.'s 
could  be  flushed  and  their  discharges  could  meet  without  quite 
filling  the  soil  pipe.  But  as  the  velocity  of  discharge  through 
a  soil  pipe  varies  according  to  the  height  through  which  the 
matter  falls,  at  least  one  more  w.c.  may  be  safely  added  to 
the  number  obtained.  We  have  now  7+1  =  8  w.c.'s  which 
may  be  discharged  into  a  4 -inch  soil  pipe  at  the  same  instant. 
It  may  further  be  safely  assumed  that  not  more  than  one- 
fourth  of  the  w.c.'s  on  a  stack  of  pipes  is  likely  to  come  into 
use  at  the  same  time,  especially  when  the  interval  of  flushing 
is  of  such  limited  duration.  Eeasoning  on  these  lines,  we 
now  have  8x4  =  32  wash-down  w.c.'s  as  a  number  which 


SOIL    AND    WASTE    PIPES  177 

may  safely  be  joined  to  one  stack  of  4-inch  pipes,  so  far  as 
the  discharging  capacity  of  the  latter  is  concerned. 

As  it  is  not  desirable  to  use  soil  pipes  larger  than 
4  inches  diameter,  an  additional  stack  should  be  provided  in 
lieu  of  one  of  an  increased  diameter  where  there  are  too 
many  closets  for  a  single  stack  of  pipes. 

Although  in  many  cases  antisiphonage  pipes  are  made 
compulsory  where  more  than  one  w.c.  is  discharged  into  a 
soil  pipe,  the  value  of  the  former  pipes  has  often  been 
questioned,  and  by  some  considered  unnecessary.  There  is 
not  the  slightest  doubt  that,  like  many  other  things,  anti- 
siphonage pipes  have  been  occasionally  overdone,  for  when  the 
spirit  of  reform  has  taken  hold  of  a  community,  whether  in 
sanitary  or  in  other  matters,  it  is  generally  the  practice  to 
rush  from  one  extreme  to  the  other.  Before  the  ventilation 
of  soil  and  waste  pipes  received  the  attention  it  does  at 
present,  these  pipes  were  generally  unventilated ;  the  result 
of  this  was,  that  when  two  or  more  w.c.'s  were  joined  to  a 
stack  of  pipes,  the  discharge  from  one  w.c.  displaced  a  certain 
volume  of  air  from  the  soil  pipe,  and  diminished  its  internal 
air  pressure,  and  as  no  air  inlets  were  provided  to  enable  the 
external  and  internal  pressures  to  be  immediately  equalised, 
one  or  more  water  seals,  which  offered  the  least  resistance, 
were  broken,  and  the  requisite  amount  of  air  was  admitted 
from  that  source. 

But  where  two  or  three  wash-down  w.c.'s  are  fixed  over 
one  another  on  a  stack  of  4-inch  pipes,  which  are  carried  up 
full  bore  to  the  roof  for  ventilation,  the  removal  of  the  water 
by  siphonage  from  any  of  the  traps  may  not  readily  occur  by 
a  single  flush,  owing  to  the  freedom  with  which  air  may  enter 
and  make  good  that  displaced  by  the  falling  body  of  water. 
It  is  from  such  a  simple  case  as  this  that  the  opponents  of 
antisiphonage  pipes  principally  draw  their  conclusions. 
^t  Numerous  experiments  have  beeu  conducted  from  time 
to  time  to  show  how  traps  may  have  their  contents  removed 
by  siphouage  and  by  other  means,  but  many  of  these  experi- 
ments possess  little  real  value,  as  they  are  often  conducted 
under  very  limited  and  unreal  conditions.  Whether  the 
water  seals  of  traps  will  be  broken  by  siphonage  or  not 
12 


178      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

will  depend  principally  to  what  extent  the  outlet  pipes  are 
charged,  the  velocity  of  discharge,  and  upon  the  provision  for 
ventilation. 

Taking  the  case  of  a  4-inch  stack  of  soil  pipes  which 
receive  discharges  from  say  four  w.c.'s,  if  the  stack  is  con- 
tinued full  bore  for  ventilation,  is  free  from  bends,  and  the 
wash-down  type  of  w.c.  is  used,  the  flushing  of  the  topmost 
w.c.  may  not  affect  the  water  seals  of  those  below  when 
no  antisiphonage  pipes  are  provided.  If,  however,  a  stack  is 
high,  and  contains  a  number  of  bends,  and  two  w.c.'s  are 
flushed  at  the  same  time,  it  becomes  quite  possible  for  the 
combined  discharges  to  remove  the  seals  from  the  lower 
fittings. 

Where  a  stack  of  soil  pipes  is  not  provided  with  anti- 
siphonage pipes,  there  is  often  a  risk  of  the  lower  traps  losing 
their  seals  by  discharging  a  pailful  of  slops  quickly  through 
one  of  the  higher  fittings.  The  top  w.c.,  of  course,  on  a 
stack  of  pipes  does  not  require  an  antisiphonage  pipe  in 
connection  with  it,  but  where  the  main  antisiphonage  pipe  is 
joined  with  a  soil  pipe  the  junction  should,  as  a  rule,  be  made 
above  the  highest  fitting. 

Sizes  of  Antisiphonage   Pipes. — The  size  of    these   pipes 
should  be  governed  by  the  general  arrangement  of  the  pipes, 
and  by  the  type  and  number  of  closets  that  are  joined  to  one  J 
stack  of  soil  pipes.     Wash-down  w.c.'s  admit  of  the  smallest 
sizes  of  antisiphonage  pipes  being  used,  as  the  discharge  in 
leaving  these  closets  is  more  prolonged  than  with  either  the  J 
valve  or  siphonic  types. 

The  object  to  be  attained  in  all  cases  is  to  have 
antisiphonage  pipes  of  a  size  that  will  allow  the  necessary 
amount  of  air  to  pass  through  them,  and  at  the  same 
time  to  prevent  undue  air  tension  in  any  branch  when  a 
volume  of  water  is  being  discharged.  There  is  no  simple 
formula  known  to  the  writer  for  determining  the  size  of 
antisiphonage  pipes ;  judgment,  along  with  a  knowledge  of 
falling  bodies  and  the  flow  of  fluids  through  pipes,  appears  to 
be  the  most  reliable  guide. 

When  water  is  discharged  from  a  w.c.  into  a  soil  pipe 
it  is  a  common  error  to  assume  that  it  falls  through  the 


SOIL    AND    WASTE    PIPES 


179 


latter  in  the  form  of  a  solid  plug.  It  will,  however,  be  found 
that  a  vertical  soil  pipe  is  only  partially  filled,  and  that  a 
discharge,  with  the  exception  of  excrement  and  paper,  etc., 
chiefly  follows  the  surface  of  the  pipe. 

If  it  is  assumed  that  3  gallons  of  water  are  discharged 
into  a  stack  of  soil  pipes  of  indefinite  height 
in  four  seconds,  then  according  to  the  law 
of  falling  bodies  the  first  particle  of  water, 
if  uninterrupted  in  its  passage,  would  have 
fallen  through  a  vertical  distance  of  256 
feet  by  the  time  the  last  particle  was  ready  ar-* 
to  fall.  In  other  words,  the  3  gallons  of 
water  near  the  end  of  the  discharge  would 
be  spread  over  a  length  of  256  feet  of  pipe. 
As  resistances  are  encountered  by  falling 
water  in  a  soil  pipe,  the  height,  of  course, 
would  be  much  less  than  that  given. 

The  length  of  4-inch  pipe  which  will 
hold  3  gallons  of  water  is  about  7  ft.  4  in. 
Of  course  the  height  of  a  soil  pipe  is  limited, 
but  the  example  simply  serves  to  show  the 
small  area  often  occupied  by  water  when  the 
latter  is  falling  through  a  pipe. 

Fig.  122  represents  four  w.c.'s  which 
are  fixed  above  one  another  and  discharge 
into  one  stack  of  pipes  ;  the  antisiphonage 
pipes  are  all  shown  to  be  2  inches  diameter, 
and  this  size  would  be  ample  where  wash- 
down  w.c.'s  were  used.  If  siphonic  w.c.'s 
were  fixed,  the  main  antisiphonage  pipe 
might  be  increased  to  2J  inch  diameter  for 
the  upper  half  of  ibs  length.  It  is  seldom 
desirable  to  use  branches  for  antisiphonage 
pipes  smaller  than  2  inches  diameter,  on  account  of  smaller 
sizes  being  more  easily  choked. 

The  effect  of  the  arrangement  of  soil  pipes  on  the  sizes  of 
antisiphonage  pipes  is  illustrated  in  Figs.  123  and  124.  If 
the  pipes  are  arranged  as  Fig.  123,  and  a  volume  of  water  is 
discharged  from  two  or  more  of  the  upper  fittings,  the  air  to 


FIG.  122.— Sizes  of 
soil  and  of  venti- 
lating pipes. 


180     DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 


replace  that  extracted  from  a  lower  horizontal  soil  pipe  branch 
would  require  to  enter  through  the  branch  antisiphonage 
pipes.  This  arrangement  may  necessitate  the  lower  horizontal 
antisiphonage  pipe  branches  being  about  3  inches  diameter. 

In  Fig.  124  the  hori- 
zontal soil  pipe  branches  are 
shown  continued  and  joined 
with  the  main  antisiphonage 
pipe,  and  as  air  tension  can 
~$  be  directly  relieved  in  any 
of  the  principal  branches  by 
this  means,  all  the  hori- 
zontal antisiphonage  pipes 
may  be  of  smaller  bore  than 
those  given  in  Fig.  123; 
neither  would  it  be  impera- 
tive to  ventilate  the  branches 
of  the  w.c.'s  nearest  the 
main  antisiphonage  pipe,  as 
shown  in  Fig.  124,  provided 
these  branches  are  only 
short. 

For  very  high  stacks  of 
4"  soil  pipes  which  have  a 
large  number  of  closets  con- 
nected with  them,  it  may 
be  found  desirable  in  a  few 
very  special  cases  to  make 
the  principal  ventilating 
pipe  a  little  larger  than  4 

FIG.  123.— Diagram  illustrating  the  effect   inches     diameter;     but     this 
the   general   arrangement   has    upon 

sizes  of  ventilating  pipes.  will  greatly  depend  upon  the 

arrangement  of  the  pipes. 

So  far  as  the  arrangement  of  the  soil  pipe  branches  is 
concerned,  that  in  Fig.  123  is  better  than  that  shown  in 
Fig.  124,  owing  to  the  possibility  in  the  latter  case  of 
matter  lodging  at  the  higher  ends  of  the  horizontal  branches. 
In  Fig.  123  the  end  w.c.  would  tend  to  keep  the  horizontal 
branches  clear  of  deposit, 


SOIL    AND    WASTE    PIPES 


181 


Unsealing  of  Traps.  —  There  are  various  ways  by  which  a 
trap  may  lose  or  partially  lose  its  water  seal,  such  as  by 
siphonage,  by  momentum,  by  capillary  attraction,  by  evapora- 
tion, by  waving  out,  and  by  the  water  being  blown  out  of  a 
trap. 

As  already  explained, 
siphonage  is  produced  when 
the  outlet  water  surface  of 
a  trap  is  subjected  to  a  less 
pressure  than  that  on  its 
inlet  side,  and  to  prevent 
siphonage,  all  that  is  neces- 
sary is  to  maintain  equi- 
librium of  the  air  pressure 
on  the  inlet  and  outlet  sides 
of  a  trap. 

Unsealing  by  momen- 
tum has  reference  to  where 
a  volume  of  water  in  flowing 
through  a  trap  encounters 
insufficient  resistance  to 
prevent  enough  water  re- 
maining in  the  trap  at  the 
end  of  the  discharge.  Traps 
in  connection  with  slop 
sinks,  or  other  fittings 
where  water  is  discharged 
rapidly  through  them,  are 
liable  to  be  unsealed  by 
momentum,  unless  their 
outlets  are  flattened  so  as 

,         T,   i       ,, 
tO    retard  a    little    the    Out- 


.  124.  —  Diagram  illustrating  the  effect 
the  general  arrangement  has  upon 
sizes  of  ventilating  pipes. 


flowing     water.       Traps    for 

baths,  ordinary   sinks,   and 

for  similar  fittings,  are  not  liable  to  be  unsealed  by  mom- 
entum ;  neither  are  the  traps  of  ordinary  lavatories,  or  those 
of  wash-down  w.c.'s  when  the  latter  are  flushed  in  the 
ordinary  manner.  When  unsealing  by  momentum  requires  to 
be  taken  into  account,  the  best  form  of  trap  to  use  is  the 


182     DOMESTIC    SANITARY    ENGINEERING    AND   PLUMBING 

anti-D  type.  An  antisiphonage  pipe  is  not  a  cure  for  loss 
of  seal  by  momentum,  and  the  remedy  lies  in  the  provision 
of  a  suitable  trap. 

Loss  of  seal  by  capillary  attraction.  When  traps  are 
not  self-cleansing,  fibrous  matter  may  hang  over  the  outlet 
side  of  a  trap  and  remove  the  water  from  it  by  capillarity. 
The  liquid  rises  through  the  interstices  of  the  matter,  and 
the  smaller  the  interstices  the  greater  the  height  to  which 
the  liquid  will  rise.  As  the  seals  of  traps  are  comparatively 
small  they  are  readily  broken  by  capillary  attraction.  To 
remedy  and  to  avoid  this  evil  all  that  is  required  is  a 
self -clean  sing  form  of  trap. 

Unsealing  by  evaporation.  In  this  country  the  water 
seal  of  a  trap  is  not  readily  removed  by  evaporation,  and 
only  where  fittings  are  out  of  use  for  a  comparatively  long 
period,  or  located  in  heated  apartments,  is  it  likely  to  lose 
its  seal  by  this  agency.  The  atmosphere,  except  when  in 
a  saturated  state,  is  constantly  taking  up  moisture  from 
any  available  source,  so  that  unless  traps  are  replenished 
periodically  with  water  their  seals  will  be  eventually  broken. 
For  houses  which  are  closed  for  long  periods  during  hot 
weather  the  water  seals  of  traps  may  be  maintained  for  a 
much  longer  time  by  putting  oil  on  their  water  surfaces. 
A  syringe  with  a  bent  tube  could  be  used  for  forcing  oil 
to  the  outlet  side  of  a  trap,  but  very  few  people  will  take 
this  trouble. 

Unsealing  by  waving  out.  Where  the  wind  can  blow 
directly  across  the  end  of  a  pipe,  or  down  it,  the  air  inside 
in  the  first  case  is  under  tension,  and  in  the  latter  case  it 
is  subject  to  more  or  less  compression  according  to  the  force 
of  the  wind.  The  partial  unsealing  of  the  traps  of  w.c.'s 
is  very  common  where  the  upper  ends  of  soil  pipes  are  left 
plain  and  unprotected  in  any  way,  and  where  no  fresh  air 
inlet  is  provided  for  the  drainage  system,  or  where  the 
inlet  is  temporarily  closed.  The  sudden  compression  of  the 
air  in  a  soil  pipe  by  a  gust  of  wind  depresses  the  water 
level  on  the  outlet  side  of  a  trap,  with  the  result  that  when 
the  force  is  spent  a  portion  of  the  water  washes  over  the 
outlet  in  regaining  its  normal  level  by  the  motion  imparted 


SOIL    AND   WASTE    PIPES  183 

to  it.  A  similar  effect  may  be  produced  when  the  air  in  a 
soil  pipe  is  rarefied  by  a  strong  current  passing  over  its  open 
end,  although  this  may  be  termed  a  case  of  siphonage. 

Unsealing  by  the  blowing  out  of  water.  The  traps 
unsealed  by  this  means  are  usually  those  which  are  situated 
at  a  low  point,  and  where  the  air  in  a  system  of  pipes  is 
put  in  compression  by  a  falling  body  of  water.  In  the 
case  of  soil  pipes  which  are  connected  directly  with  drains, 
and  where  the  latter  have  fresh  air  inlets  which  are  either 
choked  or  automatically  closed  by  an  outward  rush  of  air, 
a  discharge  from  a  w.c.  at  a  high  level  is  often  sufficient  to 
compress  the  air  in  the  drainage  system  for  a  brief  interval ; 
under  such  conditions  relief  is  obtained  by  blowing  out  the 
water  from  one  of  the  traps.  The  unsealing  of  traps  in  this 
manner  can  be  prevented  by  making  provision  for  a  free  flow 
of  air  in  either  direction. 

Waste  Pipes. — The  arrangement  of  waste  pipes  is  to  a 
great  extent  the  same  as  for  soil  pipes,  the  chief  difference 
being  that  waste  pipes  are  generally  disconnected  from  foul- 
water  drains  by  means  of  traps,  whilst  soil  pipes  are  connected 
directly  with  a  system  of  drains.  The  waste  pipes  from 
slop  sinks  and  urinals  are,  however,  exceptions  to  the  general 
rule,  and  are  treated  in  the  same  manner  as  soil  pipes. 

In  America  and  other  countries  where  climatic  conditions 
necessitate  the  soil  and  waste  pipes  being  fixed  inside  build- 
ings, in  order  to  protect  them  from  frost,  separate  soil  and 
waste  pipes  are  not  generally  used,  but  all  the  different 
sanitary  fittings  which  are  located  near  each  other  discharge 
into  a  pipe  common  to  the  whole.  Through  British  spectacles 
such  an  arrangement  is  often  thought  to  be  a  retrograde 
one,  but  when  reasoning  to  a  logical  conclusion  it  will  be 
found  sound  in  principle,  provided  "pipes  and  traps  of 
suitable  materials  are  used,  the  workmanship  is  all  that 
can  be  desired,  and  special  attention  is  paid  to  the  ventilation 
of  the  different  pipes. 

Where  it  is  essential  to  fix  soil  and  waste  pipes  inside 
buildings,  they  are  as  well  joined  together  at  a  high 
elevation  under  ordinary  conditions  as  to  be  carried  down 
separately  into  a  basement  and  there  connected  with  a 


184     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

common  drain,  provided  the  essential  conditions  of  good 
workmanship  and  suitable  materials,  etc.,  are  fulfilled. 

In  Great  Britain,  where  waste  and  soil  pipes  are  fixed 
outside  buildings,  their  separation  is  quite  defensible,  and 
where  soil  pipes  are  of  lead  it  is  practically  imperative 
that  hot  discharges  of  waste  water  flow  through  separate 
channels  to  a  drain. 

Bath  and  Lavatory  Waste  Pipes. — The  lower  portion  of 
a  stack  of  waste  pipes  is  shown  in  Fig  125,  where  a  bath 
and  lavatory  are  supposed  to  be  fixed  close  together  on 
each  of  two  floors.  The  main  waste  pipe  is  supposed  to 
be  of  cast  iron,  and  the  branches  of  copper  with  brass 
fittings. 

All  the  antisiphonage  pipes  are  of  lead,  and  are  shown 
inside  the  building ;  these  pipes  should  be  carried  up  and 
terminate  at  a  high  level,  or  be  joined  with  the  main  waste 
above  the  highest  branch. 

For  good  buildings  the  smaller  waste  pipes  should  be  of 
copper  when  discharging  hot  wrater,  and  especially  when  the 
branches  are  long.  The  first  cost  of  copper  waste  pipes  is 
rather  high,  but  they  can  be  relied  upon  and  are  durable. 
The  branch  wastes  should  not  be  too  rigidly  fixed,  but 
arranged  that  they  may  move  in  the  direction  of  their 
length.  Sufficient  space  for  movement  may  often  be  ob- 
tained with  one  or  more  bends,  but  if  a  branch  is  required 
to  be  fairly  straight  between  two  fixed  points,  and  is  of 
moderate  length,  an  expansion  joint  may  be  provided  near 
the  trap  as  at  A,  Fig.  125. 

In  copper  waste-pipe  work  a  fair  number  of  union 
connections  is  necessary,  but  in  many  cases  a  simple  form 
of  brazed  socket  joint  can  be  adopted. 

Sometimes  antisiphonage  pipes  are  also  of  copper,  and 
these  have  a  smart  appearance  when  they  are  lacquered  and 
kept  bright.  Antisiphonage  pipes,  however,  are  not  sub- 
jected to  the  same  strain  as  waste  pipes,  and  lead  pipes  are 
satisfactory  so  far  as  durability  is  concerned,  and  also  have 
the  merit  of  being  readily  fixed. 

Sizes  of  Waste  Pipes  for  Baths  and  Lavatories. — The 
waste  pipes  of  both  baths  and  lavatories  should  be  of  a 


SOIL    AND    WASTE    PIPES 


185 


reasonable  size,  so  that  these  fittings  may  be  quickly  emptied, 
and  the  discharge  of  water  be  of  service  for  aiding  in  the 
cleansing  of  the  drains.  A  waste  pipe  from  a  bath  should 


FIG.  125. — Arrangement  of  waste  and  of  ventilating  pipes  in  connection 
with  baths  and  lavatories. 

not  be  less  than  2  inches  diameter,  whilst  that  from  a 
lavatory  should  not  be  smaller  than  H  inches  diameter. 
Outlets  from  fittings  should  not  be  smaller  than  the  waste 


186     DOMESTIC    SANITARY   ENGINEERING    AND    PLUMBING 

pipes  used,  otherwise  the  latter  will  not  be  properly  cleansed, 
and  may  gradually  choke  up.  The  size  of  a  main  stack  of 
waste  pipes  should  be  about  3  inches  diameter,  and  in  special 
cases  a  size  larger  may  be  necessary. 


FIG.  126.— Arrangement  of  waste  pipes  for  a  range  of  lavatories. 

^  Arrangement  of  Waste  Pipes. — Figs.  126  to  128  show 
three  different  arrangements  of  lavatory  waste  pipes  where 
the  whole  of  the  branch  waste  pipes  and  traps  are  supposed 
to  be  of  lead ;  the  main  stack  of  pipes  in  each  case  is  of  iron. 
Where  a  trap  is  placed  beneath  each  lavatory  the  method 


FIG.  127. — Arrangement  of  waste  pipes  for  a  range  of  lavatories. 

of  arranging  the  branches  in  Fig.  127  simplifies  the  work  in 
connection  with  the  antisiphonage  pipes,  and  the  long  branch 
wastes  may  either  be  fixed  above  or  below  the  floor.  Pro- 
vision should  be  made  by  means  of  thumb-screws  for  cleansing 
out  the  long  branches  should  a  stoppage  occur  at  any  time. 


SOIL    AND    WASTE    PIPES 


187 


In  Fig.  126  the  main  antisiphonage  pipe  is  shown  on  the 
inside  face  of  the  wall,  but  it  may  be  placed  outside  if  desired. 
Instead  of  having  a  separate  trap  under  each  fitting,  occasion- 
ally a  principal  branch  waste  only  is  trapped,  as  in  Fig.  128. 
The  latter  method  is  a  cheap  and  simple  one  when  compared 
with  those  of  Figs.  126  and  127,  and  the  short  branches  from 
each  lavatory  may  be  readily  arranged  to  join  at  the  side  of 
the  inclined  waste  pipe  as  in  the  figure  given. 

It  is  always  desirable,  where  practicable,  for  branches  of 
either  soil  or  waste  pipes  to  join  the  side  instead  of  the  top 
of  a  nearly  horizontal  pipe ;  side  connections  retard  to  a  less 
extent  the  velocity  of  the  discharging  liquid,  and  the  pipes 
are  better  flushed  near  the  points  of  junction. 


FIG.  128. — Arrangement  of  waste  pipes. 

As  ranges  of  lavatories  are  required  in  large  offices, 
schools,  and  other  large  buildings,  it  is  essential  that  every 
precaution  be  taken  to  prevent  foul  air  being  emitted  from 
them,  and  so  proving  injurious  to  the  health  of  any  individual. 

Under  most  conditions  a  trap  should  be  fixed  immedi-  v 
ately  beneath  each  lavatory  where  a  number   of   lavatories    j 
are  grouped  together  ;  this  arrangement  of  the  trap  exposes 
the  least  amount  of  fouled  pipe  surface  to  the  atmosphere  of 
the  apartments  in  which  the  fittings  are  placed. 

When  a  range  of  lavatories  is  fixed  in  a  well-lighted  and 
detached  building,  which  has  ample  permanent  ventilation, 
and  a  compromise  is  sought  between  expenditure  and  hygenic 
considerations,  the  method  of  fixing  the  waste  pipes  as  shown 
in  Fig.  128  is  frequently  adopted. 


188     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

Another  method  of  dealing  with  a  group  of  lavatories,  is 
to  let  each  fitting  discharge  by  means  of  a  short  pipe  into  a 
glazed  fireclay  channel  immediately  beneath  them,  the  channel 
being  laid  to  drain  to  a  trap  which  is  placed  at  any  suitable 
point.  This  method  of  collecting  the  discharges  from  a 
range  of  lavatories  is  a  very  simple  one,  but  from  a  health 
point  of  view  it  is  bad  in  principle,  for  if  the  channels  are 
neglected  they  soon  get  in  a  filthy  state ;  the  air  which 
circulates  through  the  short  discharge  pipes  is  also  polluted 
by  contact  with  their  surfaces. 

Sizes  of  Pipes  for  Ranges  of  Lavatories. — Single  branches, 
as  previously  stated,  should  have  a  minimum  size  of  1-|  inch 
diameter;  the  horizontal  branches  should  be  from  2  to  2J 
inches  diameter,  according  to  the  number  of  lavatories  in  a 
range.  When  the  pipes  are  fixed  as  in  Fig.  126,  the  short 
branch  antisiphonage  pipes  which  are  joined  with  the  traps 
may  be  1  inch  diameter ;  a  suitable  size  for  the  horizontal 
antisiphonage  pipe  would  be  1-J-  inch  diameter,  which  may 
be  increased  to  2  inches  diameter  beyond  the  eight  lavatory. 
In  Fig.  127  each  trap  is  branched  into  a  short  length  of  1-J-- 
inch  pipe,  the  upper  end  of  which  forms  the  antisiphonage 
pipe  for  each  trap ;  with  this  exception  the  remaining  sizes 
would  be  the  same  as  for  those  in  Fig.  126. 

Slop  Sink  Waste  Pipes. — Where  discharges  of  hot  water 
are  allowed  to  flow  through  slop  sinks,  the  whole  of  the  waste 
pipes  should  be  of  iron  or  other  hard,  suitable  metal.  Special 
branches  and  connecting  pieces  should  also  be  used  to  enable 
reliable  joints  to  be  made  with  the  slop  sinks.  Owing  to  the 
contents  of  a  pail  being  quickly  discharged  through  these 
fittings,  it  is  essential  that  special  attention  be  paid  to  the 
sizes  of  the  antisiphonage  pipes  where  two  or  more  slop  sinks 
discharge  into  the  same  stack  of  pipes.  A  suitable  size  for 
branch  waste  pipes  is  3  inches  diameter,  and  for  a  main  stack 
3  to  3-|  inches  diameter.  For  a  four  storey  building,  where 
a  slop  sink  is  fixed  on  each  floor,  the  branch  antisiphonage 
pipes  to  each  fitting  may  be  2  inches  diameter,  and  for  the 
principal  antisiphonage  pipe  3  inches  diameter. 

Waste  Pipes  for  General  Sinks. — Waste  pipes  for  these 
fittings  are  often  subjected  to  unfair  usage,  and  although  lead 


SOIL    AND    WASTE    PIPES  189 

waste  pipes  and  traps  are  serviceable  for  many  sinks,  there 
are  other  cases  \vV.cre  much  stronger  pipes  and  traps  are 
essential.  In  places  where  waste  pipes  are  likely  to  be 
subjected  to  rough  usage  they  should  be  either  of  cast  iron 
or  brass  or  of  galvanised  wrought  iron.  In  ordinary  dwelling 
and  business  houses  short  lead  waste  pipes  answer  admirably, 
but  they  often  cause  trouble  when  of  considerable  length. 


FIG.  129.— Waste  pipes  for  sink. 

Of  course  if  very  hot  water  is  not  discharged  through  them, 
long  lead  waste  pipes  are  also  durable. 

Fig.  129  gives  a  waste  pipe  in  connection  with  a  scullery 
sink  where  the  former  discharges  directly  into  a  gully  trap. 
The  Model  Bye-laws  of  the  Local  Government  Board  require 
a  waste  pipe  to  discharge  on  to  an  open  channel  which  leads 
to  a  trapped  gully  grating  at  least  18  inches  distant.  The 
method  suggested  by  the  Bye-law  is  not  a  satisfactory  one, 


190     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


as  the  open  channel  frequently  gets  filthy,  and  the  force  of  the 
discharging  water  is  destroyed. 

No  overflow  is  shown  in  Fig.  129,  for,  as  stated  elsewhere, 
sinks  are  better  without  them. 

When  a  number  of  sinks  discharge  into  a  stack  of  waste 
pipes,  and  antisiphonage  pipes  are  necessary,  the  latter  should 
either  terminate  in  the  external  air  above  the  sinks,  well 
removed  from  windows  and  ventilators,  or  be  treated  in  a 
manner  similar  to  that  shown  in  Fig.  125. 


RUST 
Box. 


FIG.  130.— Rust  pockets. 


Rust  Pockets. — When  iron  pipes  are  used  for  purposes  of 
ventilation,  provision  should  be  made  for  the  interception  and 
removal  of  rust. 

For  fixing  at  the  foot  of  a  ventilating  stack,  a  rust  pocket 
similar  to  A,  Fig.  130,  is  suitable,  whilst  the  arrangement  at 
B,  Fig.  130,  may  be  adopted  where  bends  are  necessary  in 
iron  ventilating  pipes. 

Traps  for  Waste  Pipes. — These  traps  are  formed  in 
different  ways,  and  some  of  the  types  are  very  defective, 
being  deficient  in  seal  and  constructed  with  sharp  angles 
which  retain  filth.  Unless  traps  are  of  a  good  shape  they 


SOIL   AND   WASTE   PIPES 


191 


unduly  retard  the  outflow  of  water,  and  are  liable  to  be 
frequently  choked. 

The  water  seals  of  traps  for  waste  pipes  should  not  be 
less  than  1-J-  inches  deep,  and  as  a  rule  they  should  not 
exceed  2  inches  deep  for  the  large  size  of  traps. 

Three  different  forms  of  traps  are  given  in  Fig.  131, 
those  at  A  and  B  being  the  best  types  at  present  in  use. 
The  outlet  end  of  the  siphon  trap  A  takes  different  shapes 
to  suit  various  situations,  and  this  form  of  trap  may  also  be 
obtained  with  long,  straight  outlet  limbs  when  desired.  A 
siphon  trap  is  readily  unsealed  by  momentum,  but  as  this 


L..J 


FIG.  131.— Forms  of  traps. 


loss  is  chiefly  confined  to  one  when  fixed  in  connection  with 
slop  sinks,  siphon  traps  are  suitable  for  most  of  the  remaining 
fittings. 

At  B,  Fig.  131,  Hellyer's  anti-D  trap  is  given  ;  the  throat 
of  the  trap  is  restricted  in  area,  and  this  enables  it  to  be 
readily  cleansed.  In  cross  section  its  outgo  is  nearly  square, 
the  corners  being  rounded  a  little  instead  of  being  left  sharp. 
Owing  to  the  shape  of  the  anti-D  trap  it  requires  to  be  cast, 
and  although  it  is  a  little  dearer  than  a  drawn  lead  trap  it 
is  much  stronger. 

The  type  of  trap  at  C,  Fig.  131,  can  only  be  described  as 
a  poor  one.  It  usually  has  too  shallow  a  seal,  the  depth  of 


192     DOMESTIC    SANITARY    ENGINEERING   AND    PLUMBING 

which  can  neither  be  seen  nor  readily  ascertained ;  the  water 
passages  are  of  a  poor  form,  and  the  principal  changes  of 
direction  are  too  "abrupt. 

Traps  which  have  movable  parts  in  the  form  of  flaps  or 
balls  are  not  suitable  for  fixing  to  waste  pipes ;  they  are  not 
reliable,  and  neither  are  they  self-cleansing. 


CHAPTEE  VIII 
DRAINAGE   OF   HOUSES   AND   OTHER   BUILDINGS 

A  DRAINAGE  system  should  be  designed  upon  sound  prin- 
ciples, and  constructed  in  a  manner  to  prevent  its  being 
the  cause  of  the  pollution  of  the  subsoil  and  a  carrier  of 
polluted  air  back  to  and  into  buildings.  Numerous  cases  of 
typhoid  fever  and  other  illnesses — many  proving  fatal — have 
been  due  to  sewage  polluted  water  through  defective  drains. 
Sewer  and  drain  air  may  also  be  the  means  of  disseminating 
the  germs  of  disease. 

It  is  not  intended  here  to  deal  with  the  different  forms 
of  old  brick  and  stone  built  drains, — these  being  chiefly  of 
historical  interest,— but  to  devote  the  space  at  disposal  to 
modern  drainage  work. 

The  value  of  a  good  drainage  system  is  now  generally 
appreciated,  and  for  many  buildings  cast-iron  drains  are 
rapidly  superseding  those  of  earthenware  for  the  conveyance  of 
foul  liquid  matter.  The  substitution  of  iron  for  earthenware 
drains  has  chiefly  arisen  through  the  difficulty  of  maintaining 
the  latter  in  a  sound  state  for  any  great  length  of  time  after 
being  laid  and  covered  in.  Very  often  it  has  been  found  that 
fine  cracks  have  occurred  at  the  sockets  of  earthenware  pipes, 
due  to  the  expansion  of  the  jointing  material,  even  when  care 
has  been  exercised  in  carrying  out  the  work. 

When  joints  are  made  with  portland  cement  the  pipes 
are  very  rigid,  and  if  unequal  settlement  of  the  ground  takes 
place  the  pipes  readily  fracture  on  account  of  their  unyielding 
nature.  When  earthenware  drains  are  laid,  as  they  frequently 
are,  with  unskilled  labour,  and  jointed  with  portland  cement, 
there  is  little  wonder  that  pipes  and  joints  are  readily  broken, 


194     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

especially  when  defects  occur  in  work  which  has  been  well 
supervised  and  executed  by  experienced  men. 

As  the  failure  of  earthenware  drains  is  frequently  due  to 
the  use  of  portland  cement  as  the  jointing  material,  other 
substances,  such  as  bituminous  cements,  which  possess  some 
degree  of  elasticity  are  now  often  used.  In  ground  of  moderate 
firmness,  and  which  is  not  subject  to  frequent  vibration, 
earthenware  drainage  work  may  be  satisfactorily  carried  out, 
provided  a  suitable  elastic  jointing  material  is  used,  and 
provided,  further,  that  the  pipes  are  of  good  quality  and  are 
properly  laid. 

The  advantages  of  earthenware  drains  are  smoothness, 
freedom  from  corrosion,  and  the  durability  of  the  material. 

Iron  drains  possess  the  merits  of  greater  strength,  reduced 
number  of  joints,  and  they  can  be  made  to  remain  air  and 
water-tight  for  long  periods  after  being  laid.  Spigot  and  socket 
joints  should  be  used  for  iron  pipes,  and  when  the  former 
are  caulked  with  metallic  lead  they  will  yield  a  little  should 
any  slight  settlement  take  place.  Iron  drains  may  occasionally 
be  of  a  smaller  diameter  than  those  of  earthenware,  as  the 
former  may  be  obtained  in  a  larger  range  of  sizes,  and  may 
flow  full  and  under  pressure  in  suitable  situations. 

The  chief  drawbacks  of  iron  drains  are,  their  inner  sur- 
faces are  not  so  smooth  as  those  of  earthenware,  they  are 
subject  to  corrosion,  and  therefore  have  a  limited  life.  The 
initial  cost  of  iron  drainage  work  is  also  greater. 

When  dilute  acids  are  frequently  discharged  into  a  system 
of  drains,  earthenware  pipes  and  fittings  are  essential,  as  iron 
would  be  rapidly  corroded.  It  is  sometimes  contended  that 
an  iron  drain  in  connection  with  a  residence  is  liable  to  be 
attacked  by  a  periodical  discharge  of  dilute  acid,  such  as  may 
take  place  when  spring  cleaning  is  proceeding.  An  iron  drain, 
however,  is  not  likely  to  be  appreciably  affected  at  such  times, 
as  the  acid  used  would  be  in  a  very  diluted  state  when  it 
reached  the  drain,  and  the  greasy  surface  of  the  latter  would 
offer  sufficient  protection  to  the  metal  in  most  cases. 

The  minimum  size  of  underground  drain  that  is  generally 
used  is  4  inches  diameter,  but  in  many  cases  a  3-inch  drain 
could  be  advantageously  adopted  for  many  branches.  So  far 


DRAINAGE    OF    HOUSES    AND    OTHER    BUILDINGS       195 

as  the  capacity  of  a  4-inch  drain  is  concerned,  it  is  frequently 
capable  of  discharging  a  volume  several  times  greater  than  it 
will  ever  be  required  to  discharge.  When  rain-water  is  kept 
separate  from  foul-water  drains,  a  4-inch  main  drain  would 
be  large  enough  to  dispose  of  the  waste  discharges  from  a  very 
large  building. 

Definitions. — Foul  water  drains  are  generally  under- 
stood to  be  those  which  receive  the  discharges  from  any 
sanitary  fitting  in  a  building,  waste  water  from  wash-houses, 
and  dirty  waste  water  which  is  discharged  into  gully  traps. 

Kain,  or  clean,  water  drains  are  those  which  receive  rain- 
water directly  from  the  roof  of  the  buildings,  and  also 
subsoil  water. 

Drainage  Design.  —  The  chief  points  to  consider  when 
arranging  a  system  of  drains  are  : — 

1.  That  they  are  laid  with  self -cleansing  gradients. 

2.  That  they  are  arranged  in  straight  lines  between  fixed 

points,  with  true  alignment  of  inverts. 

3.  That  principal  junctions  and  changes  of  direction  are 

made  in  inspection   chambers,  to  enable  any  part 
of  a  system  to  be  readily  accessible. 

4.  That  every  part  of  a  system  is  adequately  ventilated. 

5.  That  the  main  drain  is  disconnected  from  the  sewer. 

6.  That  all  levels  be  correctly  obtained. 

7.  That   after   completion  the   drains  will  be   capable  of 

remaining  water  and  air-tight. 

8.  That    materials    are    of    the   best   of   their   respective 

kinds. 

9.  That    all    drains    are    laid    outside    buildings    where 

practicable. 

10.  That  all  unnecessary  traps  are  avoided. 

11.  That   the   size   of   drains    are    proportionate  to  their 

requirements. 

12.  That  all  air  inlets  and  outlets  are  located  in  positions 

well  removed  from  windows  and  other  places  that 
afford  a  direct  passage  for  drain  air  into  buildings. 
Fig.    132  represents  the  block   plan  of  a  detached  villa 

residence,  and  a  method  of  arranging  the  drains  is  also  shown. 

Although  the  whole  of  the  rain  and  waste  water  discharge  into 


196      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


oue  system,  the  length  of  foul-water  drain  is  kept  as  short  as 
practicable,  and  the  whole  system  admits  of  good  ventilation. 


SR 


INDEX. 

5.R  =  5oil  Pi]ae. 

WP.  —  Waste,  Pipe. 

QT.  —  GulleyTraja. 

R.W.P.  —  Rain-Water  Pipe. 

V.R  —  Ventilating  Pipe. 

5.W.R  —  5inK  Waste  ?i|De. 

D.T.  T-  Disconnecting  Trap. 


R.P/.P. 


FIG.  132.  —  Drainage  plan  of  a  detached  house. 

The  disconnecting  trap  No.  1  cuts  off  a  length  of  earthen- 
ware rain-water  drain  from  the  foul-water  system,  and  the 
rain-water  pipes  in  this  case  discharge  directly  into  the  branch 


DRAINAGE   OF    HOUSES    AND   OTHER   BUILDINGS       197 

drains.  When  a  drain  conveying  clean  water  is  disconnected 
from  the  foul-water  drains  as  shown,  a  trap  is  not  required  at 
the  foot  of  a  rain-water  pipe.  In  Fig.  132  there  are  two  soil 
pipes  shown,  and  it  will  be  observed  that  each  of  these  is 
arranged  to  come  at  the  head  of  a  section  of  foul-water  drain, 
and  to  act  as  air  outlet  ventilators.  The  branch  drain  into 
which  the  kitchen  sink  discharges  is  ventilated  by  a  special 
ventilating  pipe,  which  is  indicated  on  plan.  It  is  intended 
that  the  kitchen  sink  waste  shall  discharge  into  an  ordinary 
gully  trap,  as  a  grease  trap  is  not  often  necessary  for  a  villa 
of  the  size  shown.  Where  a  waste  pipe  and  a  rain-water  pipe 
are  near  each  other,  they  may  both  discharge  into  the  same 
trap.  All  the  chief  lengths  of  drains  in  Fig.  132  are  readily 
accessible  by  means  of  chambers,  which  are  provided  at  the 
principal  turnings  and  branches.  A  little  consideration  will 
decide  the  best  positions  for  chambers,  as  the  expense  they 
involve  prevents  their  general  use  at  all  junctions  and 
turnings. 

Drains  should  not  be  laid  close  to  walls  if  it  can  be  avoided, 
and  where  they  pass  through  them  provision  should  be  made 
to  prevent  the  pipes  taking  any  of  the  weight  of  the  walls 
should  any  settlement  take  place. 

In  large  buildings,  and  in  terrace  houses,  where  a  drain 
discharges  into  a  sewer  in  a  front  street,  it  is  often  imperative 
to  lay  drains  through  the  buildings.  In  such  cases  ample 
provision  should  be  made  to  enable  a  stoppage  to  be  removed 
without  interfering  with  the  floors  of  these  places. 

Drains  under  floors  should  be  of  heavy  section  cast  iron 
but  no  concrete  foundations  are  necessary  for  these  pipes 
provided  the  ground  is  moderately  firm  on  which  they  are 
laid. 

Foundations  for  Drains. — When  laying  earthenware  drains, 
concrete  is  often  desirable,  and  in  some  cases  its  use  is  essential. 
Fig.  133  shows  three  different  ways  in  which  concrete  may  be 
used.  At  A  an  earthenware  pipe  is  shown  laid  in  ordinary 
firm  ground,  where  fine  concrete  is  used  for  packing  at  the 
sides  of  the  pipes  after  the  latter  have  been  jointed  and  tested. 
A  fairly  wide  concrete  foundation  is  indicated  at  B,  Fig.  133, 
for  poor  ground,  fine  concrete  being  used  as  before  for  packing 


198      DOMESTIC    SANITARY   ENGINEERING    AND    PLUMBING 


at  the  sides  of  the  pipe.    At  C  the  drain  is  surrounded  with  con- 
crete.   This  form  of  construction  is  necessary  when  earthenware 

drains  are  laid  in  deep  ground, 
to  take  the  weight  of  the  earth, 
and  also  where  they  are  laid 
near  the  surface  of  the  ground 
which  is  subjected  to  heavy  traffic 
passing  over  it.  When  foul- 
water  drains  are  of  earthenware, 
and  laid  inside  buildings,  they 
should  be  well  surrounded  with 
concrete.  The  covering  of  drains 
with  concrete  adds  greatly  to 
their  cost,  so  that  where  con- 
crete is  freely  used  the  differ- 
ence in  cost  between  iron  and 
stoneware  drainage  work  may 
not  be  much. 

It  is  necessary  when  laying 
pipes  that  they  firmly  rest  on 
the  ground  for  the  whole  of 
their  length,  for  if  pipes  simply 
rest  upon  their  sockets  they  are 
liable  to  be  fractured  by  the 
superincumbent  earth. 

Connections  with  Drains, — 
When  a  foul-water  drain  passes 
near  the  foot  of  a  stack  of  rain- 
water pipes,  the  latter  frequently 
discharge  directly  into  a  gully 
trap,  which  is  joined  with  the 
drain  ;  if,  however,  a  rain-water 
pipe  is  some  distance  from  a 
foul-water  drain,  it  should  be 
treated  as  in  Fig.  134.  Here 
the  rain-water  pipe  discharges 

into  an  access  bend,  an  iron  grid  being  provided  to  enable 
air  to  flow  freely  in  or  out.  The  disconnecting  trap  should 
be  fixed  as  closely  to  the  foul -water  drain  as  possible,  in  order 


<C 


FIG.  133. — Foundations  for  eai'th- 
enware  drains. 


DRAINAGE   OF   HOUSES   AND   OTHER   BUILDINGS       199 

to  limit  the  length  of  branch  drain  which  is  not  subjected  to 
direct  ventilation.  This  method  of  treating  rain-water  drains 
is  also  shown  on  plan,  Fig.  132. 

The  form  of  connection  Fig.  134  is  often  adopted  for 
receiving  the  discharges  from  a  lavatory,  or  similar  fitting, 
which  is  located  at  the  end  of  a  long  branch  drain.  As 
before,  the  disconnecting  trap  is  joined  with  the  nearest 
foul- water  drain,  but  a  solid  cover  is  placed  on  the  access 
bend  instead  of  an  iron  grid.  Air  may  freely  circulate 


FIG.  134. — Connection  between  rain-water  pipe  and  foul- water  drain. 

through  the  branch  drain  and  waste  pipe,  the  inlet  side 
of  the  disconnecting  trap  serving  as  an  inlet  or  outlet  for  air, 
as  the  case  may  be.  By  treating  a  stack  of  waste  pipes  in 
the  manner  stated,  a  separate  ventilating  pipe  for  the  branch 
drain  becomes  unnecessary. 

Junctions  and  Bends. — The  junctions  that  should  be  used 
for  branch  drains  are  those  that  curve  towards  the  main 
channel  in  the  direction  of  the  flow,  and  also  the  V-shaped 
forms.  Eight-angle  junctions  are  often  serviceable  for  testing 
purposes  when  suitably  located,  but  they  should  not  other- 


200      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


wise  be  used,  owing  to  the  resistance  they  offer  to  the  flow  of 

liquids. 

In  general,  bends  should  be  made  to  a  large  radius,  that 

changes  of  direction  may  be  as  easy  as  possible,  sharper  bends 

only  being  used  in  confined  situations  where  the  use  of  easier 

ones  is  impracticable. 

Chambers   and  Openings  for   Access.  —  Chambers   may  be 

classified  into    two   principal   groups.     (1)  Those   which   are 

constructed  with  open  channels,  and  require  air-tight  covers  ; 

and  (2)  those  which  are 
formed  with  closed  channels 
and  are  provided  with  suit- 
able means  of  access,  and 
where  air  -  tight  manhole 
covers  are  not  essential.  The 
first  type  possesses  the  advan- 
tages of  the  branch  drains 
being  under  better  control 
than  in  a  closed  system  (un- 
less  special  fittings  are  used), 
and  the  inverts  of  the  chan- 
nels are  exposed  to  view 
when  the  manhole  cover  is 
removed.  The  use  of  the  first 
type  is  better  for  foul-water 
drains  which  are  fixed  outside 
buildings,  and  for  rain-water 
drains. 


FIG.  135. — Plan  of  chamber  when 
formed  with  stock  fittings. 


The  second  type  of  chamber  is  suitable  for  foul-  water 
drains  which  are  located  close  to  and  inside  buildings,  as  no 
reliance  is  then  necessary  upon  air-tight  manhole  covers  and 
air-tight  brickwork  construction. 

Where  open  channels  are  used  for  chambers  inside  buildings, 
any  little  defect  in  the  sealing  of  the  manhole  covers  admits  a 
direct  passage  for  drain  air  into  buildings. 

In  first  class  drainage  work  the  inside  face  of  a  chamber 
is  often  formed  with  glazed  bricks,  and  for  work  of  a  less 
costly  character  a  sound  red  brick  will  often  suffice,  whilst  a 
blue  brick  facing  gives  the  happy  medium.  Open  channels  in 


DRAINAGE   OF    HOUSES    AND   OTHER   BUILDINGS       201 

chambers  are  frequently  formed  of  half  pipes,  half  bends  and 
junctions,  but  better  channels  are  produced  by  having  a 
chamber  bottom  in  one  or  more  pieces,  according  to  its  size. 
In  Fig.  135  a  plan  of  a  collecting  chamber  is  given,  where  the 
channels  are  formed  from  stock  fittings.  The  chief  drawback 
of  this  arrangement  is,  that  when  a  discharge  takes  place 
through  a  branch  like  that  at  A,  a  portion  of  the  water  is 
liable  to  rush  over  the  outer  edge  of  the  bend  and  up  the 
benching,  and  thus  destroy  the  effective  flushing  power  of  the 
water. 

A  better  shape  of  channel  bend,  and  one  which  prevents 
the  drawback  mentioned,  is  given  in 
Fig.  136.  Where  a  branch  drain  enters 
a  main  channel,  the  invert  of  the  former 
should  be  higher  than  that  of  the  latter, 
and  for  a  main  open  channel  to  be 
satisfactory  it  should  take  a  deeper  form 
than  the  semicircular  type.  Fig.  137 
gives  a  plan  and  part  section  of  a  collect- 
ing chamber,  where  the  whole  of  the 
chamber  bottom  is  formed  in  one  piece 
of  glazed  fireclay;  the  branches,  it  will 
be  observed,  are  arranged  so  as  to  con- 
centrate the  discharges  into  the  main 
channel,  but  each  chamber  bottom  re-  ™' 


quires   to    be    specially   constructed    to 

suit  the  circumstances  of  each  particular  case. 

When  chambers  are  constructed  with  closed  channels,  the 
latter  may  be  either  of  stoneware  or  of  cast  iron,  the  design 
being  similar  in  each  case  excepting  that  the  methods  of 
securing  their  access  covers  may  differ. 

A  double  branch  piece  for  cast-iron  drainage  work  is  given 
in  Fig.  138  ;  the  access  opening  should  be  as  large  as  practicable 
so  as  to  facilitate  the  inspection  of  the  branch  drains,  and  the 
cover  may  be  secured  by  pinching  screws  and  cross  bridles, 
or  by  other  suitable  means. 

Sizes  of  Chambers.  —  The  sizes  of  chambers  are  controlled 
by  their  depth  and  the  number  of  branches  which  require  to 
enter  them  ;  the  minimum  size  of  shallow  chambers  is  about 


202     DOMESTIC    SANITARY    ENGINEERING   AND   PLUMBING 

2  feet  square.  Deep  chambers,  of  course,  must  be  large 
enough  for  a  man  to  enter  and  to  work  inside  them,  so  that 
the  smallest  size  for  the  bottom  of  a  deep  chamber  should  be 
about  4  ft.  by  2  ft.  3  in. ;  this  size  may  be  reduced  to  about 
2  ft.  3  in.  square  or  to  other  suitable  dimensions  when  about 


FIG.  137. — Plan  of  chamber  bottom  when 
formed  with  special  channel  blocks. 


FIG.  138. — Branch-piece  for  iron 
drain. 


5  ft.  above  the  bottom  of  a  chamber.  In  Fig.  138  the  access 
junction  rests  upon  a  concrete  foundation,  and  after  the  pipes 
have  been  jointed  gravel  may  be  filled  in  and  well  rammed 
around  the  connections,  the  surface  of  the  gravel  being  covered 
with  a  layer  of  cement  mortar  about  1  inch  in  thickness. 
A  little  space  will  require  to  be  left  near  the  ends  of 


DRAINAGE    OF    HOUSES    AND    OTHER    BUILDINGS       203 

the  access  openings,  in  order  that  the  iron  bridles   may  be 
removed. 

A  longitudinal  section  of  an  open  channel  disconnecting 
chamber  with  trap  is  given  in  Fig.  139.  The  trap  should  be 
placed  immediately  beneath  the  manhole  cover,  for  if  the  former 
should  get  choked  at  any  time  it  may  be  possible  to  remove  the 
stoppage  from  the  opening  above.  Iron  stirrups  should  be  built 
in  the  walls  of  deep  chambers  about  12  inches  apart  to  provide 


FIG.  139. — Longitudinal  section  through  a  disconnecting  chamber. 

a  permanent  means  for  getting  in  and  out.  Where  a  raking  arm 
is  provided  on  the  sewer  side  of  a  trap,  as  in  Fig.  139,  care 
should  be  taken  that  the  stopper  is  properly  secured,  or  the 
trap  may  be  rendered  useless. 

Fresh  air  may  be  admitted  to  an  open  channel  disconnect- 
ing chamber  through  a  perforated  cover  when  a  chamber  is 
favourably  located,  but  it  is  often  necessary  to  fix  a  fresh  air 
inlet  a  short  distance  away  from  a  manhole  cover. 

For  iron  drains,  and  where   closed   channels   are  used,  a 


204     DOMESTIC    SANITARY    ENGINEERING  AND    PLUMBING 

similar  disconnecting  chamber  to  that  given  in  Fig.  140  may 
be  adopted.  It  will  be  observed  that  the  invert  of  the  channel 
in  connection  with  the  trap  has  a  quicker  gradient  than  that 
of  the  drain ;  this  is  very  desirable,  as  the  increased  velocity 
imparted  to  the  discharging  matter  compensates  to  a  great 
extent  for  the  resistance  offered  by  the  trap. 

Manhole  Covers  for  house  drains  are  usually  of  cast  iron, 
and  many  different  patterns  are  made.  For  situations  where 
heavy  weights  are  likely  to  pass  over  them  a  heavy  section 
should  be  adopted.  In  public  institutions,  such  as  schools, 
it  is  often  desirable  to  use  covers  which  may  be  locked  in 
order  to  prevent  them  being  removed  by  children.  Air- 


FIG.  140. — "  Bland's  "  iron  channel  and  trap. 

tight  covers  depend  for  their  soundness  upon  tallow,  oil,  and 
similar  substances ;  the  frames  of  these  covers  are  provided 
with  grooves  which  are  filled  witli  the  jointing  material,  and 
the  rims  of  the  covers  are  embedded  into  it. 

Drain  Traps. — The  construction  of  traps  for  drainage 
work  should  be  such  as  to  oiler  the  minimum  resistance 
to  the  flow  of  liquids  which  pass  through  them ;  surfaces 
which  are  liable  to  be  fouled  should  be  of  the  smallest  possible 
area,  and  all  drain  traps  should  be  provided  with  large  flat 
bases  that  they  may  be  properly  fixed.  Many  drain  traps 
are  little  better  than  small  cesspools  on  account  of  their  size 
and  the  large  volume  of  water  they  hold ;  such  traps  are  most 
objectionable,  as  they  are  never  properly  cleansed  and  become 
very  offensive. 


DRAINAGE   OF    HOUSES    AND    OTHER    BUILDINGS       205 


FIG.  141.— Trap  for  intercepting  sand,  etc. 


A  gully  trap  of  good  construction  may  be  rendered  faulty 

by  waste  water  from  sanitary  fittings   first   passing   through 

a  grating,  instead  of   discharging   directly  into   it,  and   in   a 

direction  that  will  thoroughly  scour  it  out.     For  yards,  and 

situations  where   a   large 

amount   of    sand   or   fine 

gravel    is    liable     to     be 

washed    into     a    trap,    a 

self-cleansing  type  should 

not   be    used,   but   one 

similar    to    Fig.    141    is 

suitable,  as  any  debris  is 

retained  at  the  bottom  of 

the  trap.     Traps  like  Fig. 

141  require  to  be  cleaned 

out  periodically,  and  their 

use    is    not    desirable   in 

house  drainage  work  except  for  the  special  purpose  stated. 
Disconnecting  Traps. — The  object  of  a  disconnecting  trap 

is  to  break  the  direct  passage  between  a  drain  and  a  sewer, 

but  to  leave  a  course  through  which  liquid  matter  may  flow. 

The  value  of  a  dis- 
connecting trap 
has  often  been 
questioned,  and  its 
abolition  would 
suit  many  en- 
gineers and  sur- 
veyors, who  are 
anxious  to  use  the 

FIG.  142. -Poor  form  of  disconnecting  trap.  goil  pipeg  of  build_ 

ings  to  aid  in  the 

ventilation  of  sewers.  Although  the  disconnecting  trap  is 
not  free  from  drawbacks,  its  retention  is  ensured  for  some 
considerable  time,  unless  some  better  method  of  drain  and 
sewer  ventilation  to  that  generally  adopted  comes  into  force. 

There  are  various  forms  of  disconnecting  traps,  but  they 
may  generally  be  classified  into  three  distinct  types,  as  repre- 
sented by  Figs.  142  to  144 ;  each  type  is  made  in  both  earthen- 


206      DOMESTIC   SANITARY    ENGINEERING  AND    PLUMBING 


ware  and  iron.  In  Fig.  142  both  inlet  and  outlet  are  on  the 
same  level,  and  this  type  admits  only  of  a  sluggish  flow  through 
it,  and  is  liable  to  retain  a  large  amount  of  solid  matter. 
The  inlet  of  Fig.  143  is  above  the  water-line  of  the  trap,  so 

that  the  accelerated  velocity 
of  the  discharge,  due  to  the 
sudden  fall,  aids  in  scouring 
out  the  trap.  When  com- 
paring Figs.  143  and  144, 
the  shape  of  the  latter  at 
its  inlet  more  nearly  con- 
forms with  the  path  described 
by  a  discharging  volume  of 
water.  A  trap  like  Fig.  143 
may  in  many  cases  allow  a 

FIG.  143.— Buchan's  disconnecting  trap,     discharge    to    strike    its    op- 

posite   side,  and   so    reduce 

the  effective  flushing  power  of  the  water.  The  raking  arm 
of  Fig.  144  is  also  an  advantage,  as  rods  may  be  readily  inserted 
and  a  stoppage  removed  on  the  sewer  side  of  the  trap. 

The  seal  of  a  disconnecting  trap  should  not  be  less  than 
1J  inches  deep,  and  a  greater 
depth  than  2  inches  is  likely 
to  cause  a  stoppage  to  take 
place.  Gully  traps  when 
placed  at  the  bottom  of  rain- 
water pipes  should  have  seals 
from  2  to  2J  inches  deep,  and 
in  special  cases  they  may  have 
3  inches  of  seal  on  account  of 
loss  by  evaporation  in  periods 
of  drought. 

Grease  Traps  are  of  two 
principal  types :  those  which 
require  the  grease  to  be  re- 
moved from  them  periodically  by  hand,  and  those  from  which 
grease  is  automatically  discharged  through  drains  by  the  aid 
of  flushing  water. 

Fig.    145   shows   the   first   type  of  grease  trap,  whilst  a 


FIG.  144. — Disconnecting  trap. 


DRAINAGE   OF   HOUSES    AND   OTHER   BUILDINGS       207 

flushing  type  is  illustrated  in  Fig.  146.  As  a  rule  grease 
traps  are  filthy  receptacles,  and  should  not  be  used  unless 
absolutely  necessary.  For  private  houses  they  are  seldom 


FIG.  145. — Buchan's  grease  trap. 

required,  but  are  often  essential  in  large  hotels,  restaurants, 
and  similar  places,  where  a  large  amount  of  greasy  matter 
is  discharged  into  drains.  Grease  traps  to  fulfil  their  purpose 


FIG.  146. — Adams'  flushing  grease  trap. 

require  to  hold  a  large  volume  of  water,  in  order  to  solidify 
the  hot  liquid  grease  as  it  enters  them;  when  the  volume 
of  water  is  comparatively  small  in  a  grease  trap,  there  is 
danger  of  the  trap  being  rendered  useless  by  its  contents 


208      DOMESTIC   SANITARY    ENGINEERING    AND   PLUMBING 

getting  overheated,  and  by  the  grease  flowing  into  the  drain 
in  a  liquid  state. 

In  the  flushing  type  of  trap  the  grease  is  discharged 
through  the  drain  in  a  solid  state,  for  in  this  form  it  is  not 
likely  to  cause  any  trouble.  Many  flushing  grease  traps, 
however,  are  too  small  to  serve  any  useful  purpose,  and  such 
fittings  are  often  fixed  where  an  ordinary  gully  trap  would 
be  preferable. 

Tidal  Traps. — In  low-lying  districts,  where  sewers  dis- 
charge into  tidal  rivers,  or  into  rivers  which  rapidly  rise  in 
time  of  storm,  the  basements  of  buildings  in  such  areas  are 


FIG.  147. — Couzen's  tidal  or  anti-flooding  trap. 

subject  to  periodical  flooding  unless  means  are  taken  to  prevent 
it.  The  back  flow  of  water  through  drains  may  be  arrested  in 
different  ways,  such  as  by  fixing  simple  flap  valves  at  the 
ends  of  the  drains  where  they  join  the  sewers,  or  at  convenient 
points  in  the  drains  themselves.  The  flaps  are  hinged,  and 
swing  outward  when  a  discharge  takes  place  from  drain  to 
sewer ;  but  a  return  flow  presses  the  flap  on  to  a  seating,  which 
if  properly  arranged  makes  a  water-tight  joint.  As  galvanised 
iron  or  other  metallic  flaps  are  liable  to  stick  or  otherwise  get 
out  of  order,  ball  traps  similar  to  those  shown  in  Figs.  147 
and  148  are  preferable.  Strong  copper  balls  are  used  in  these 
traps,  and  a  back  flow  of  water  presses  the  balls  on  to 
rubber-faced  seatings.  The  trap  shown  in  Fig.  147  is  suitable 


DRAINAGE   OF   HOUSES   AND    OTHER   BUILDINGS       209 

for  fixing  in  a  basement  area  or  similar  situation,  whilst 
the  disconnecting  type  of  trap,  Fig.  148,  is  better  suited 
for  receiving  several  branch  drains  to  which  ordinary  gully 
traps  are  attached.  A  chamber  of  ample  size  should  be 
constructed  for  the  latter  type  of  trap,  to  enable  the  covers 
to  be  removed  when  required. 

Other  forms  of  tidal  traps  are  used,  but  those  shown  are 
the  most  reliable  types. 

Drainage  of  Basements  and  Sewage  Lifts. — Speaking 
generally,  the  drainage  of  a  basement  in  an  ordinary  dwelling 
presents  no  special  difficulty.  Where  a  basement  is  used  as 
a  wash-house,  provision  is  of  course  necessary  for  disposing  of 


FIG.  148. — Couzen's  tidal  or  anti-flooding  trap. 

the  waste  water.  The  most  efficient  method  of  doing  this  is  to 
provide  an  outside  area  in  which  a  gully  trap  is  fixed,  and  to 
make  the  floor  of  the  cellar  fall  towards  the  area ;  this  arrange- 
ment dispenses  with  the  use  of  a  trap  in  a  basement  floor, 
and  in  the  event  of  the  area  trap  being  unsealed  by  evapora- 
tion, drain  air  may  not  directly  escape  into  the  basement,  but 
the  greater  portion  may  rise  through  the  area  grating  and 
become  diffused  with  the  outside  atmosphere.  That,  however, 
would  be  largely  governed  by  the  state  of  the  external  air  with 
respect  to  its  temperature  and  humidity. 

In  many  large  buildings  with  basements  and  sub-basements, 
liquid  waste  matter  requires  to  be  raised  to  a  higher  level 
before  it  can  be  discharged  into  a  sewer.  For  such  buildings 
the  waste  discharges  from  the  upper  storeys  would  be  con- 


210      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

ducted  in  the  usual  manner  to  the  sewers,  thus  leaving  the 
discharges  of  sewage  or  waste  liquids  at  the  lowest  levels  to 
be  dealt  with. 

Appliances  for  raising  sewage  may  take  various  forms, 
such  as  pumps  (which  may  be  worked  either  by  hand,  steam 
power,  water  power,  or  electricity),  ejectors,  and  sewage  lifts, 
etc. 

The  most  suitable  method  to  adopt  chiefly  depends  upon 
the  power  available,  the  nature  of  the  waste  liquid,  and  the 
volume  to  be  raised.  Where  only  small  volumes  of  waste 
matter  require  to  be  dealt  with,  a  suitably  arranged  sump  and 
a  small  hand-pump  might  be  adopted.  For  dealing  with  larger 
volumes  of  sewage  a  water  motor  and  pump  could  be  installed, 
and  also  arranged  to  be  automatic  in  action.  A  motor  may 
readily  be  obtained  which  may  be  worked  with  the  water 
pressure  from  a  street  main. 

Adams'  lift,  Fig.  149,  is  suitable  for  raising  sewage  in 
certain  cases,  such  as  where  the  water  to  work  it  may  after- 
wards be  utilised  for  supplying  sanitary  fittings,  etc.,  at  a  lower 
level,  or  where  water  costs  very  little.  The  apparatus 
Fig.  149  consists  of  the  following  parts  :  an  automatic  flushing 
tank  A,  a  cylinder  B,  siphon  C,  a  sewage  cylinder  D,  an  air 
pressure  transmitting  pipe  E,  a  non-return  valve  F,  and  a 
sewage  receiver  G.  Assuming  the  apparatus  to  have  just 
discharged,  and  the  automatic  flushing  tank  A  refilling,  the 
cylinder  B  would  be  full  of  air  at  atmospheric  pressure  on 
account  of  the  open  pipe  H  being  joined  to  the  flush  pipe. 
Sewage  flowing  from  sump  G  may  enter  the  sewage  cylinder 
D,  but  is  prevented  from  returning  by  the  non-return  valve 
F.  The  action  of  the  apparatus  is  as  follows  :  When  the 
flushing  tank  A  is  full  of  water,  its  contents  are  automatically 
discharged  into  the  cylinder  B  ;  as  this  cylinder  fills  with  water, 
air  is  confined  and  compressed,  the  air  pressure  being  trans- 
mitted by  means  of  pipe  E  to  the  surface  of  the  sewage  in 
the  cylinder  D,  the  sewage  in  turn  being  displaced  from  the 
cylinder  through  the  outlet  pipe  P  into  the  chamber  shown ; 
from  the  chamber  the  sewage  can  gravitate  to  the  sewer. 
From  cylinder  B  the  water  is  discharged  by  means  of  the 
siphon  C,  the  capacity  of  the  flush  tank  A  being  sufficient 


DRAINAGE   OF   HOUSES   AND   OTHER   BUILDINGS      211 

to  fill  cylinder  B  and  to  charge  the  siphon  as  well.  The  tank 
B  may  be  placed  in  any  convenient  position,  but  the  head  of 
the  flushing  tank  will  require  to  exceed  the  height  to  which 
sewage  is  to  be  raised.  The  outlet  leg  of  the  siphon  C  is 


FIG.  149.— Adams'  lift. 

shown  discharging  into  a  clean- water  storage  tank,  from  which 
the  water  may  be  withdrawn  as  desired.  A  suitable  overflow 
pipe  would  be  necessary  for  tank  T  to  prevent  the  latter  over- 
flowing. 

Any  surplus  water  could  be  utilised  for  flushing  drains  by 


212     DOMESTIC   SANITARY   ENGINEERING   AND   PLUMBING 

taking  a  pipe  from  tank  T,  a  few  inches  below  the  overflow,  to 
supply  an  automatic  flushing  tank  at  a  lower  point. 

A  fresh  air  inlet  pipe  is  shown  joining  near  the  sump  G, 
and  an  air  outlet  is  supposed  to  be  provided  at  the  head  of  the 
drain.  Where  water  which  is  raised  from  a  low  to  a  higher 
level  is  not  of  a  very  foul  nature,  it  may  be  delivered  into  a 
gully  trap,  instead  of  into  a  chamber  as  in  Fig.  149. 

Fig.  150  shows  the  drainage  system  for  a  large  house, 
where  the  greater  portion  of  the  roof  water  is  conducted  to  a 
storage  tank.  The  sewer  is  supposed  to  be  in  front  of  the 
house,  and  a  storage  tank,  together  with  rain-water  separator, 
is  located  at  the  back.  The  whole  of  the  foul- water  drains,  with 
the  exception  of  a  few  very  short  branches,  is  accessible  from 
chambers,  and  the  head  of  each  section  of  foul- water  drain  has 
a  suitable  outlet  ventilator.  Instead  of  showing  a  trap  at  the 
foot  of  the  waste  pipe  where  the  drain  from  same  delivers 
into  chamber  No.  1,  a  disconnecting  trap  is  placed  near  the 
chamber,  and  the  length  of  branch  drain  ventilated  by  means 
of  the  waste  pipe  which  is  supposed  to  be  carried  full  bore 
above  the  eaves.  Where  the  branch  drains  are  short,  gully 
traps  are  indicated  for  receiving  the  discharges  directly  from 
the  waste  pipes,  and  a  trap  is  better  located  at  the  foot  of  a 
waste  pipe  unless  it  is  the  cause  of  a  length  of  drain  being 
without  adequate  ventilation. 

As  the  greater  portion  of  the  rain-water  drains  is  separated 
from  the  foul-water  drainage,  no  traps  are  necessary  for  this 
section,  and  ordinary  access  bends  should  be  placed  at  the 
bottom  of  the  rain-water  pipes.  Access  bends,  along  with  the 
chambers  shown,  make  the  rain-water  drains  readily  accessible. 
The  rain-water  separator  S,  Fig.  150,  prevents  the  first  portion 
of  the  rainfall  from  entering  the  storage  tank,  and  diverts  it 
through  the  by-pass  P  into  the  overflow  from  the  tank.  The 
tank  overflow  is  supposed  to  discharge  into  a  water-course  or 
other  suitable  place,  but  assuming  it  were  necessary  for  it  to 
discharge  into  the  sewer,  then  the  overflow  could  join  with 
chamber  No.  2.  A  disconnecting  trap  would  of  course  be 
essential  on  the  overflow,  and  one  with  a  specially  deep  seal 
would  be  preferable  unless  measures  were  adopted  to  keep  the 
trap  fully  sealed.  If  it  were  necessary  for  the  overflow  from 


DRAINAGE   OF   HOUSES    AND   OTHER   BUILDINGS       213 

the  tank  to  discharge  into  the  drainage  system  as  suggested, 
chamber  No.  2  and  the  drain  from  it  would  require  to  be 
deeper  than  with  the  arrangement  shown;  under  such  con- 


ditions the  disconnecting  chamber  No.  5  might  be  better 
located  at  the  right  side  instead  of  at  the  left  side  of  the 
house,  as  in  Fig,  150,  The  position  of  the  disconnecting 


214     DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 

chamber  should  be  controlled  as  far  as  practicable  by  the 
depth  of  the  drains. 

The  whole  of  the  foul-water  drains  are  supposed  to  be  of 
cast-iron,  and  are  indicated  by  bold  lines,  stoneware  pipes 
being  used  for  the  rain-water  drains,  and  indicated  in  double 
lines. 

Drainage  of  Stables  and  Byres. — Stables  are  better  drained 
by  means  of  open  channels  in  the  floors,  the  channels  being 
arranged  to  discharge  into  one  or  more  traps  which  are  located 
near  the  walls  in  the  open  air.  Traps  inside  stables  should 
be  avoided  if  possible,  but  if  their  use  is  found  desirable,  good 
strong  iron  traps  with  hinged  grids  should  be  used.  Open 
channels  should  be  as  shallow  as  practicable,  and  so  formed 
that  there  is  no  likelihood  of  them  tripping  and  laming  a  horse, 
In  some  cases  channels  in  stables  are  covered  with  iron  grids, 
but  these  are  often  more  objectionable  than  traps ;  for  unless 
channel  grates  are  regularly  taken  up  and  cleansed  they  get 
into  a  very  unsatisfactory  state.  Channels  when  exposed  to 
view  are  as  a  rule  kept  in  a  better  state  than  those  which  are 
covered  with  grates. 

The  method  of  disposing  of  the  liquid  waste  matter  from 
stables  will  largely  depend  upon  the  location  of  these  build- 
ings. Where  land  is  available  the  urine  should  drain  to  a 
suitable  sump,  that  it  may  be  periodically  applied  to  the  land. 
In  other  cases  where  no  land  is  available,  the  discharges 
from  stables  may  require  to  flow  into  a  sewer.  For  stables 
where  urine  is  utilised  for  its  manurial  value  a  separate 
system  of  drains  will  be  required  to  take  away  waste  water, 
and  also  that  from  roofs  and  paved  surfaces.  The  underlying 
principles  for  stable  drainage  are  practically  similar  to  those 
which  govern  house  drainage  work. 

It  is  usually  desirable  to  disconnect  stable  drains  from 
those  of  dwellings,  so  that  they  may  be  ventilated  independ- 
ently of  each  other. 

Byres  are  drained  in  a  manner  similar  to  that  adopted 
for  stables,  but  the  channels  which  are  used  for  stables  would 
be  useless  for  the  former  buildings. 

Connections  of  Drains  with  Sewers. — When  pipe  sewers 
are  laid,  junctions  are   provided  at  intervals  to  receive  the 


DRAINAGE  OF  HOUSES  AND  OTHER  BUILDINGS   215 

drains  from  existing  property,  and  also  to  a  great  extent  for 
properties  to  be  erected  at  a  future  date.  Many  cases  occur, 
however,  when  a  connection  with  a  pipe  sewer  is  necessary 
and  where  no  provision  has  been  made.  In  earthenware 
sewers  junctions  cannot  be  properly  fixed  after  the  pipes 
are  laid  unless  three  or  four  pipes  are  removed,  or  unless 
special  forms  of  junctions  are  used.  The  removal  of  say 
three  lengths  of  pipe  during  a  constant  flow  of  sewage  creates 
some  trouble,  and  often  one  pipe  only  is  removed  for  the 
insertion  of  a  junction.  In  such  a  case,  when  an  ordinary 
junction  is  used  it  is  necessary  to  shorten  it,  in  order  to  get 
it  in  position  ;  by  this  method  both  joints  of  the  main  channel 


FIG.  151. — Socketed  saddle  piece  for  making  a  connection  with  a  sewer. 

are  only  at  the  best  half  socketed,  and  the  cavities  remaining 
fill  with  putrid  matter. 

For  making  a  branch  connection  with  an  existing  pipe 
sewer,  a  hole  may  be  cut  into  the  side  of  the  pipe,  and  a 
socketed  saddle  piece  arranged  as  in  Fig.  151.  The  saddle  piece 
is  provided  with  a  curved  flange,  and  when  properly  jointed 
and  supported  good  connections  can  be  made  without  disturb- 
ing the  principal  line  of  pipes. 

To  connect  a  drain  with  an  existing  brick  sewer,  a  proper 
junction  block  should  be  used  as  in  Fig.  152  ;  the  bricks  require 
to  be  carefully  cut  away,  the  block  inserted,  and  the  brick 
work  again  made  good.  Junction  blocks  are  made  in  glazed 
stonewrare  for  either  4J-inch  or  9-inch  brickwork,  and  to  suit 
different  sizes  of  sewers.  It  is  necessary  to  insert  a  junction 
block  well  up  on  the  side  of  an  egg-shaped  sewer  in  order  that 


216     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


the  end  of  the  drain  shall  not  be  submerged  with  rather  more 
than  the  normal  flow  of  sewage.  A  length  of  drain  which  is 
partially  submerged  soon  begins  to  silt  up. 

Ventilating  and  Flushing  of  Drains. — The  object  of 
ventilating  drains  is  to  prevent  the  accumulation  of  dangerous 
gases  in  them,  and  to  dilute  any  gas  as  generated  with  large 
volumes  of  atmospheric  air.  The  flushing  of  drains  is  closely 
allied  with  their  ventilation,  as  this  prevents  putrid  matters 
lodging  in  drains  and  keeps  them  in  a  cleanly  state. 

In  many  cases  the  ventilation  of  drains  is  a  simple  matter, 
but  in  others  it  is  more  difficult  to  carry  out  owing  to 

unfavourable  situations  for 
air  inlets  and  outlets. 
Where  only  natural  forces 
are  engaged  in  drain  venti- 
lation, the  air  cannot  be 
regulated  to  flow  at  all 
times  in  one  particular 
direction.  In  many  cases 
the  air  currents  are  often 
reversed,  and  there  are  also 
periods  when  ventilation  is 
nearly  stagnant. 

For  a  villa  residence, 
where  the  fresh  air  inlet 
of  a  drain  may  be  suitably 
placed  in  a  garden  some 

distance  from  the  building,  it  matters  very  little  whether  the 
air  currents  in  the  drains  are  frequently  reversed  or  not. 
Where,  however,  the  front  and  back  of  a  building  come  close 
up  to  thoroughfares,  as  is  the  case  with  many  city  buildings, 
the  effect  of  reversed  currents  in  drains  is  of  more  importance, 
and  a  method  of  drain  ventilation  may  be  necessary  where 
foul  air  cannot  escape  at  a  low  level. 

Fig.  153  gives  a  method  of  ventilating  the  drains  for 
the  latter  class  of  building.  At  the  back  a  soil  pipe  is 
represented,  and  at  the  front  of  the  building  a  low-level  fresh 
air  inlet  is  shown,  which  is  joined  with  a  high-level  ventilating 
pipe.  To  the  fresh  air  inlet  a  reliable  form  of  non-return 


FIG.  152. — Connection  for  a  drain  and 
brick  sewer. 


DRAINAGE   OF   HOUSES   AND   OTHER   BUILDINGS      217 

valve  requires  to  be  attached,  to  prevent  drain  air  escaping 
at  that  point  when  the  air  currents  in  the  system  are  reversed. 
The  ventilating  pipe,  which  is  carried  up  the  front  of  the 
building,  serves  either  as  an  inlet  or  outlet  for  air,  and  it  also 
prevents  the  air  in  the  drain  being  put  in  a  state  of  com- 
pression when  the  inlet  valve  is  closed,  and  when  a  large 
volume  of  water  is  being  discharged  from  a  high  level  into 
the  drain. 

In  drain  ventilation    the  air   should  be  able  to  flow   in 


FIG.  153. — Drain  ventilation. 


either  direction,  and  at  the  same  time  it  should  not  be  allowed 
to  escape  at  any  point  where  it  may  prove  disagreeable  or 
injurious  to  health. 

There  should  always  be  a  marked  difference  between  the 
levels  of  inlets  and  outlets  in  drain  ventilation,  for  where 
only  high-level  inlets  and  outlets  are  used  ventilation  is  often 
stagnant. 

The  flow  of  air  through  drains  is  affected  by  the  following : 
Relative  humidity  of  the  atmosphere,  the  number  of  bends  in 
drains  and  ventilating  pipes,  difference  between  internal  anct 


218     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


external  temperatures,  force  of  the  wind,  and  the  arrangement 
of  fresh  air  inlets  and  outlets. 

It  is  often  assumed  that  air  flows  with  more  or  less 
considerable  velocity  through  drains,  and  that  a  ventilating 
stack  acts  something  like  a  chimney.  The  flow  of  air 
through  drains,  however,  is  often  very  sluggish,  on  account  of 
the  resistance  which  the  air  encounters. 

The  humidity  of  the  atmosphere  has  a  marked  effect  on 
drain  ventilation,  and  when  the  atmosphere  is  in  a  state  of 
saturation,  or  when  its  percentage  of  humidity  is  high, 
ventilation  is  often  at  a  standstill, 
whilst  with  a  dry  atmosphere,  other 
conditions  being  equal,  it  is  usually 
active. 

Heat  and  cold  have  their  effect ; 
in  winter  many  ventilating  pipes  which 
are  exposed  to  the  cold  are  readily 
converted  from  outlets  into  inlets, 
owing  to  the  air  in  the  pipes  being 
heavier  than  that  in  the  drains. 

Eetardation  of  the  flow  of  air  due 
to   bends   is   often    considerable,  and 
most  forms  of  cowls  are  also  offenders 
in  the  same  respect.     For  drain  venti- 
lation cowls   should  not  be   used,  as 
they  more  frequently  retard  the  flow 
of  air  than  accelerate  its  movement. 
The  extracting  power   of   the   wind  is  not   always  fully 
utilised    in   drain   ventilation,   as    much    depends   upon   the 
position  of  the  outlet  ventilators. 

A  good  form  of  mica  flap  air  inlet  valve  is  given  in 
Fig.  154. 

Flushing  Drains. — To  keep  a  drain  in  a  satisfactory  state 
of  cleanliness,  it  is  occasionally  necessary  to  resort  to 
flushing;  this  may  arise  through  the  character  and  volume 
of  the  waste  liquids  discharged,  or  to  the  gradient  of  a 
drain  being  insufficient  to  produce  a  self-cleansing  velocity. 

In  order  to  cleanse  drains,  automatic  flushing  tanks  are 
generally  installed  at  suitable  points,  to  enable  large  volumes 


FIG.  154.— Barker's  fresh 
air  inlet  valve. 


DRAINAGE   OF   HOUSES    AND   OTHER    BUILDINGS       219 


-C 


'-ffl 


of  clean  water  to  be  rapidly  discharged  into  the  drains. 
These  tanks  take  different  forms,  but  they  may  be  divided  into 
the  following  types  : — 

(a)  Those  which  are  provided  with  vacuum  action  siphons, 

and  will  work  with  a  slow  feed. 

(b)  Those  with  plenum  siphons,  and  which  also  will  operate 

with  a  slow  feed. 

(c)  Those  with  siphons  and  reversed  action  ball  cocks,  and 

which   require    a   quick   feed  just   prior   to   their 
discharge. 

(d)  Those    with    mechanical 

parts,  such  as  tippers, 
floats,  valves,  etc. 

Automatic  flushing  tanks  are 
constructed  of  galvanised  iron, 
and  of  concrete  or  brickwork; 
the  former  are  suitable  for  fixing 
inside  buildings,  whilst  the  latter 
are  suitable  when  they  require 
to  be  placed  below  ground  level. 

Fig.  155  gives  .Rodger  Field's 
automatic  flushing  tank,  which 
is  representative  of  type  a.  At 
the  top  of  the  stand-pipe  P  a 
short  taper  pipe  C,  which  forms 
an  inverted  frustum  of  a  cone, 
is  attached;  the  outer  covering 
or  dome  D  contains  an  air-hole 

H,  and  a  trap  T  is  formed  with  a  small  seal  by  sub- 
merging the  end  of  the  stand-pipe.  The  action  of  the  tank  is 
as  follows :  When  the  water  in  the  tank  is  above  the  air-hole 
H,  air  is  confined  in  the  upper  part  of  the  dome  and  stand- 
pipe  ;  as  the  filling  of  the  tank  proceeds,  the  confined  air  is 
further  compressed,  until  it  overcomes  the  resistance  offered 
by  the  water  seal  of  the  trap,  when  small  volumes  of  air  escape. 
Each  time  an  escape  of  air  takes  place,  the  water  rises  higher 
in  the  annular  space  between  the  dome  and  the  stand-pipe, 
until  it  finally  reaches  the  top  of  the  latter  and  overflows; 
the  water  upon  falling  through  the  stand-pipe  gradually  dis- 


T 


FIG.  155. — Field's  automatic 
flushing  tank. 


220     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

places  some  of  the  confined  air,  and  after  a  time  the  air  press- 
ure in  P  is  so  reduced  that  it  is  no  longer  capable  of  resisting 
that  of  the  external  air,  when  the  discharge  is  started  and  the 
water  siphoned  from  the  tank. 

The  purpose  of  the  inverted  frustum  C  is  to  make  the 
water  fall  clear  of  the  sides  of  the  pipe,  for  if  it  merely  trickled 
down  the  sides  no  displacement  of  air  would  be  effected,  and 
the  siphon  would  not  be  brought  into  action. 

The  air-hole  H  is  necessary  to  break  siphonage  at  the  end 
of  a  discharge,  and  when  it  is  omitted  or  choked  water  is  liable 
to  be  withdrawn  as  quickly  as  it  enters  the  tank,  after  once 
siphonage  has  been  established. 

A  vacuum  action  tank  will  also  get  out  of  order  if  the 
interval  between  the  flushes  is  very  prolonged,  owing  to  the 
loss  of  air  from  the  stand-pipe.  The  effect  of  this  loss  is  to 
allow  water  to  dribble  away  as  quickly  as  it  enters  a  tank 
when  once  the  latter  is  full. 

A  by-pass  with  a  stop-cock  S,  Fig.  155,  is  often  provided  for 
this  class  of  tank,  to  enable  the  water  to  be  discharged  when 
the  tank  is  out  of  working  order  due  to  loss  of  air. 

Adams'  plenum  action  automatic  siphon,  Fig.  156,  is  shown 
fixed  in  a  brick  tank,  and  illustrates  the  general  principles 
embodied  in  type  6.  The  construction  of  plenum  siphons  by 
different  makers  differs  a  little  in  details,  such  as  in  the  pro- 
vision made  for  starting,  stopping,  and  charging  siphons,  but 
all  require  deep  seals,  the  depth  of  which  is  regulated  by  the 
depth  of  water  desired  in  the  tanks. 

The  action  of  the  siphon  in  Fig.  156  is  as  follows:  After 
water  has  risen  in  the  tank  above  the  end  of  the  tube  T, 
air  is  confined  in  the  long  vertical  leg  P  of  the  siphon ;  the 
gradually  increasing  head  of  water  transmits  pressure  to 
the  confined  air,  which  in  turn  begins  to  displace  the  water 
from  P,  and  through  the  outlet  of  the  siphon.  When  a  pre- 
determined water-line  has  been  reached  in  the  tank  the  level 
of  the  water  in  the  stand-pipe  will  be  down  to  the  lip  L, 
when  with  further  filling  of  the  tank  a  volume  of  the 
confined  air  is  displaced  from  P,  followed  by  water,  and  the 
siphonic  action  in  consequence  is  started.  At  C,  Fig.  156,  the 
diameter  of  the  outgo  is  contracted  in  order  that  the  air  shall  be 


DRAINAGE   OF   HOUSES   AND    OTHER   BUILDINGS       221 

discharged  clear  of  the  sides  of  the  pipe,  and  aid  in  the  starting 
of  the  siphon  by  reducing  resistance  in  the  outlet  leg.  The 
tube  T  serves  the  double  purpose  of  confining  the  necessary 
amount  of  air  in  the  siphon,  and  of  effectively  breaking  siphonic 
action  after  the  period  of  discharge. 

Type  c  automatic  flushing  tank  is  illustrated  by  Fig.  157, 
and  is  provided  with  a  reversed  action  ball-cock ;  a  small  bib- 
cock is  often  used  to  regulate  the  filling  of  the  tank,  and  when 
the  latter  is  nearly  full  the  ball-cock  is  opened  full  bore,  and 


FIG.  156. — Adams'  automatic  flushing  siphon. 

the  siphon  is  charged  and  brought  into  action.  The  automatic 
siphon  Fig.  157  would  be  useless  with  a  slow  feed  when 
nearing  its  point  of  discharge,  as  a  slow  inflow  of  water  would 
be  unable,  owing  to  the  form  of  the  siphon,  to  dislodge  suffi- 
cient air  from  it.  A  rapid  inflow,  however,  when  the  tank  is 
nearly  full,  dislodges  the  air,  and  siphonage  is  started. 

In  order  for  all  forms  of  automatic  siphons  to  work  properly 
they  must  have  a  free  discharge,  and  no  air  must  be  confined 
in  their  outlet  pipes. 

The  tipper  tank  Fig.  158  is  provided  with  trunnions,  and 
depends  for  its  action  upon  the  shifting  forward  of  its  centre 


222     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


of  gravity  when  the  tipper  is  filled  with  water ;  this  causes  the 
tipper  to  cant  forward  and  discharge  its  contents,  when  it  again 
rights  itself  owing  to  the  centre  of  gravity  of  the  empty  tipper 

being  again  moved  nearer 
the  back,  which  is  occa- 
sionally weighted.  Tippers 
are  very  noisy  in  action, 
although  this  can  be  largely 
counteracted  by  providing 
buffers  against  which  they 
may  strike. 

Flushing  tanks  similar 
to  Fig.  158  are  simple  in 
construction,  but  they  are 
liable  to  get  out  of  work- 
ing order  owing  to  the 
wear  on  the  trunnions. 

The  length  of  drain 
which  can  be  adequately 
cleansed  with  an  automatic 
flushing  tank  will  depend 

upon  the  gradient  of  the  drain,  upon  the  initial  velocity  of 
the  flushing  water,  upon  the  condition  of  the  drain,  and  upon 
the  volume  of  water  and  size  of  siphon  used. 
To  give  the  discharging 


water  a  high  initial  velo- 
city, the  flushing  tank 
should  be  fixed  a  few  feet, 
where  possible,  above  the 
drain  to  be  flushed.  The 
velocity  with  which  the 
discharge  enters  a  drain  is 
soon  diminished,  and  gradu- 
ally decreases,  until  it  fin- 
ally acquires  that  due  to  the  gradient  of  the  drain. 
Decline  of  velocity,  however,  does  not  take  place  at  a 
uniformly  decreasing  rate,  but  is  greatest  per  unit  length  of 
drain  where  the  velocity  is  highest. 

It  is  desirable  when  drains  are  very  long,  and  where  flushing 


FIG.  157. — Automatic  flushing  tank. 


FIG.  158.— Tipping  flusher. 


DRAINAGE   OF   HOUSES    AND   OTHER    BUILDINGS      223 


is  necessary,  to  provide  tanks  at  two  or  more  points  which  are 
some  distance  apart,  rather  than  to  discharge  their  combined 
volumes  into  a  drain  at  one  point. 

Rain  water  may  be  utilised  for  flushing  drains  in  many 
cases  by  constructing  a  suitable  tank  for  the  purpose. 

The  following  table  gives  sizes  of  siphons  and  volumes  of 
water  necessary  for  flushing  drains. 

TABLE  II. 


Size  of  drain  to  be 
flushed. 

Size  of  Siphon. 

Capacity  of  flush 
tank. 

4  inches  diameter. 
.   5       ,,            » 
6       „ 

8       „ 
9       „ 

3    inches  diameter. 
3*      „ 
4        „ 
4*      „ 

5        „ 

25  to     40  gallons. 
40  „     60       „ 
60  .,     80      „ 
80  „  120      „ 
120  ,,  180       „ 

Methods  of  Laying  Drains  to  given  Gradients. — After  the 
plans  have  been  prepared  for  a  drainage  system,  levels  may  be 
taken  and  sections  prepared  which  show  the  gradients  and 
depth  of  drains.  For  a  small  system  which  discharges  into  a 
sewer  of  ample  depth  plotted  sections  may  be  unnecessary, 
but  their  use  is  practically  imperative  for  large  drainage 
systems.  The  depth  of  drains  is  greatly  increased  where  base- 
ments require  to  be  drained,  but  a  system  should  be  designed 
as  far  as  possible  to  avoid  unnecessary  lengths  of  deep  drains. 

Different  methods  are  adopted  for  obtaining  true  alignments 
of  drains  between  given  points,  such  as  by  the  use  of  (a)  chalk 
lines,  (b)  straight  edges,  (c)  sight  rails  and  boning  rods. 

Chalk  Lines. — When  a  chalk  line  is  used  it  is  often 
placed  against  the  sockets  of  the  pipes,  midway  between  the 
top  and  one  side,  so  as  to  serve  the  purpose  of  testing  the 
straightness  of  drains  in  two  directions  at  the  same  time. 
A  method  of  giving  a  length  of  drain  a  given  gradient  where 
a  level  is  not  used,  is  to  drive  in  the  ground  a  strong 
wooden-peg  at  each  end  of  the  excavated  track ;  the  peg  at 
the  higher  end  is  driven  so  as  to  leave  its  top  level  with 
the  bottom  of  the  pipe.  One  end  of  a  long  parallel  straight- 


224     DOMESTIC   SANITARY   ENGINEERING   AND    PLUMBING 

edge  is  then  placed  on  the  peg,  and  by  the  aid  of  a  spirit 
level  the  straight-edge  is  set  level.  A  chalk  line  is  afterwards 
tightly  stretched  from  end  to  end  of  the  track,  so  as  to  just 
rest  on  the  top  of  the  straight-edge  for  the  whole  of  its  length. 
In  this  manner  at  the  lower  end  of  the  track  a  point  is  obtained 
which  is  in  line  with  the  top  of  the  straight-edge  in  question. 
If  now  at  the  lower  end  a  peg  has  been  used  of  sufficient 
length,  the  level  obtained  by  the  chalk  line  can  be  marked 
upon  it.  The  lower  fixed  point  for  the  gradient  is  then 
obtained  by  deducting  from  the  mark  already  on  the  peg  the 
height  through  which  the  drain  must  fall,  plus  the  width  of 
the  straight-edge.  When  the  latter  point  has  been  measured 
off,  the  upper  portion  of  the  peg  can  be  sawn  off,  so  as  to  make 
its  top  level  with  the  bottom  of  the  drain.  After  the  first 
drain  pipe  has  been  placed  in  position,  another  pipe  may  be 
temporarily  laid  in  its  place  at  the  higher  end,  and  the  chalk 
line  stretched  between  them. 

A  drawback,  however,  which  attends  the  use  of  chalk  lines 
is  their  liability  to  sag,  and  thus  give  more  or  less  irregular 
gradients. 

Short  Straight-Edges  and  a  spirit  level  are  sometimes 
used  for  laying  drains.  In  this  case  either  parallel  or  tapered 
straight-edges  are  used,  the  latter  being  made  to  agree  with 
the  gradients  of  the  drains.  This  method  is  less  satisfactory 
than  the  first  one  described,  as  each  pipe  is  fixed  only  with 
respect  to  that  previously  laid,  and  deviation  from  the  correct 
gradient  may  readily  occur. 

Boning  Rods  and  Sight  Rails. — The  best  way  of  obtaining 
true  gradients  is  by  the  use  of  sight  rails  and  boning  rods. 
Sight  rails  are  placed  across  the  trench,  and  consist  of  two 
strong  vertical  posts  which  are  securely  fixed  in  position,  with 
a  horizontal  cross-piece  attached.  A  boning  rod  represents  a 
rough  form  of  T  square,  with  an  iron  shoe  or  stirrup  at  its 
lower  end  for  laying  on  the  inverts  of  the  pipes.  Boning  rods 
may  either  be  made  in  adjustable  forms,  to  enable  their  lengths 
to  be  increased  and  shortened  as  desired,  or  constructed  with 
upright  pieces  in  one  length. 

The  usual  method  of  fixing  sight  rails  is  shown  in  Fig.  159, 
where  the  uprights  are  fixed  in  drain  pipes  and  held  in  position 


DRAINAGE   OF   HOUSES    AND   OTHER   BUILDINGS       225 

by  ramming  the  latter  full  of  earth.  A  sight  rail  is  fixed  at 
each  end  of  a  straight  drain  track,  and  when  the  latter  is  very 
long,  intermediate  sight  rails  may  be  fixed  at  intervals  of  about 
60  to  80  yards.  It  is  essential  that  sight  rails  be  fixed  in 
positions  which  are  not  liable  to  be  disturbed  by  subsidence, 
or  be  moved  in  any  other  irregular  manner. 

A  front  and  side  view  of  an  adjustable  boning  rod  are 


FIG.  159.— Method  of  fixing  sight  rails. 

given  in  Fig.  160,  where  S  denotes  the  iron  stirrup,  which  is  of 
sufficient  length  to  pass  the  faucet  and  to  rest  on  the  invert 
of  the  pipe,  whilst  T  shows  the  iron  bands  and  thumb-screws 
for  regulating  the  length  of  the  rod. 

In  Fig.  161  a  length  of  drain  is  indicated  which  requires  to 
be  laid  with  a  gradient  of  1  in  56  between  points  A  and  B. 
The  invert  of  the  drain  at  B  is  20  feet  above  an  assumed 
datum  line,  which  may  be  adopted  for  the  system  of  which 
the  length  AB  forms  a  part.  The  top  of  a  peg  at  the  road 
'5 


226     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


VIEW. 


VIEW 


surface  is  29  feet  above  the  datum  line,  and  the  invert  of  the 
drain  at  B  is  9  feet  below  the  top  of  the  peg,  or  20  feet  above 
the  datum  line  as  shown. 

At  points  A  and  B  the  posts  of  the  sight  rails  are 
erected,  and  at  the  higher  point  the  cross-rail  may  be 
fixed  at  any  convenient  height.  The  height  of  the  cross-rail 
at  the  lower  point  is  determined  by  the  aid  of  an  ordinary 
level,  which  is  placed  midway  between  the  two  sight  rails  in 

order  to  eliminate  errors  of  colli- 
1  mation.  The  length  of  drain 
under  consideration  is  196  feet, 
and  with  a  gradient  of  1  in  56 
the  difference  in  level  between 
the  two  ends  must  be  3*5  feet. 
Assuming  a  levelling  staff  is  held 
on  the  top  of  the  cross-rail  at  B, 
and  the  reading  is  3 -12  feet,  the 
FRONT  staff  when  held  on  the  top  of 
the  lower  sight  rail  should  read 
3-124-3-5  =  6-62  feet.  To  obtain 
the  position  of  the  latter,  the 
staff'  may  be  held  against  one  of 
the  uprights  and  the  height  of 
the  staff  adjusted  until  the  read- 
ing is  6'62,  when  a  mark  can  be 
made  on  the  upright  at  the 
bottom  of  the  staff ;  to  the  latter 
point  the  cross -rail  should  be 
securely  fixed,  and  an  ordinary 
FIG.  160.— Adjustable  boning  rod.  spirit  level  may  be  used  for 

levelling     the     cross-rail.      The 

boning  rod  is  then  adjusted  to  the  required  length,  which 
for  the  case  given,  taking  the  data  at  point  A,  would  be 
(26-26 -16-5)  +  (10-01- 6-62)  =  13-15  feet.  As  the  invert  of 
the  drain  must  be  parallel  with  the  line  of  sight,  the  cross  head 
of  the  boning  rod  should  be  exactly  in  line  when  fixed  on  the 
invert  at  any  point,  and  when  looking  over  the  sight  rails 
from  one  to  the  other. 

When  sight   rails   and   boning  rods   are   used  for  laying 


10-01 


S  -  91 


73 

E 

o 


-    O-02 


228      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

drains,  every  length  of  pipe  or  channel  is  laid  with  reference 
to  the  datum  line. 

Timbering  Trenches. — It  is  essential  when  excavating, 
that  the  sides  of  drain  trenches  be  properly  supported  to 
prevent  them  falling  in.  The  manner  of  timbering  trenches 
depends  chiefly  upon  their  depth,  upon  the  nature  of  the  earth, 
and  upon  the  position  in  which  the  trenches  require  to  be  cut. 

When  cutting  through  stiff  clays  only  a  few  timbers  are 
required,  even  where  the  trenches  are  fairly  deep,  but  for  a 
loose  earth  timbers  should  be  freely  used,  or  the  sides  of  the 
trenches  are  liable  to  fall  in,  especially  in  wet  weather. 

The  timbers  used  are  generally  termed  poling  boards, 
walings,  and  struts.  Poling  boards  are  of  any  convenient 
length  and  width;  they  vary  from  1  to  2  inches  in 
thickness,  and  are  vertically  fixed  against  the  earth  to  be 
supported.  Walings  are  strong  timbers,  and  are  horizontally 
placed  in  front  of  the  poling  boards ;  these  are  of  various 
widths  and  thickness,  and  are  fixed  near  the  tops  and  bottoms 
of  the  poling  boards.  Where  poling  boards  are  very  long, 
walings  are  also  placed  at  intermediate  points. 

Struts  are  cross-pieces  which  hold  the  timbers  in  position ; 
in  depth  struts  should  nearly  equal  the  widths  of  the  walings, 
and  be  from  1J  inches  and  upwards  in  thickness. 

In  deep  cuttings  struts  should  be  fixed  immediately  over 
each  other  in  order  to  allow  room  for  excavating,  and  be 
placed  at  intervals  of  6  to  8  feet  along  the  track. 

Trenches  should  be  cut  tapering  a  little  inwards,  so  that 
in  case  of  a  slip  or  subsidence  the  timbers  would  tend  to 
wedge  together,  instead  of  falling  from  their  respective  places. 

When  quick  or  running  sands  are  encountered,  timbering 
requires  to  be  specially  well  done  to  keep  the  sand  out  of  the 
trench.  For  such  cases  grooved  and  tongued  poling  boards 
are  necessary,  and  any  open  joint  requires  to  be  well  caulked 
with  tow  or  other  suitable  material. 

It  is  also  important  that  special  attention  be  paid  to 
timbering  when  a  trench  is  cut  near  to  and  lower  than  the 
foundations  of  a  building,  or  the  stability  of  the  latter  may  be 
endangered.  Care  must  also  be  observed  when  removing 
timbers  from  cuttings  of  the  latter  class ;  the  principal  timbers 


DRAINAGE    OF    HOUSES    AND    OTHER   BUILDINGS       229 

in  such  cases  should  be  left  in  position  when  the  earth  is 
replaced,  in  order  to  avert  any  disturbance  of  the  structure  due 
to  settlement  of  the  newly  replaced  earth. 

Drain  Testing. — During  the  laying  of  drains  it  is  desirable 
that  some  reliable  test  be  applied  from  time  to  time  as  the 
work  proceeds,  and  whilst  the  pipes  are  bare,  as  any  defect  is 
more  readily  located  and  more  readily  righted.  A  final  test 
should  also  be  applied  at  the  completion  pf  a  scheme,  both  to 
test  the  general  soundness  of  the  drains  and  the  resistance 
offered  by  the  water  seals  of  traps. 

The  general  tests  applied  to  drains  are  four  in  number,  and 
are  known  as  hydraulic,  air,  smoke,  and  smell  tests.  In  the 
hydraulic  test  a  drain  is  filled  with  water,  after  first  firmly 
plugging  up  its  lower  end  by  means  of  a  suitable  plug  or 
stopper.  Water  may  be  run  into  a  drain  from  any  convenient 
point,  but  the  head  upon  a  fireclay  drain  should  not  as  a  rule 
greatly  exceed  7  feet,  or  water  may  show  signs  of  oozing 
through  the  pores  of  the  material.  Stoneware  pipes  of  good 
quality  would  stand  a  greater  head  without  showing  similar 
signs  of  leakage. 

After  a  length  of  drain  has  been  charged,  the  water  level 
should  be  maintained  for  not  less  than  30  minutes.  At  first, 
however,  even  when  earthenware  drains  are  sound,  the  water 
level  may  slowly  fall  for  a  short  time,  on  account  of  the 
material  absorbing  a  certain  volume  of  water.  Where  a  number 
of  branches  occur  in  any  particular  section  under  test,  a  few 
gully  traps  may  require  to  be  plugged  in  order  that  the  neces- 
sary head  of  water  may  be  obtained. 

Test  junctions  are  very  useful  in  drains,  as  a  system  may 
be  divided  into  comparatively  small  sections  for  testing 
purposes. 

For  testing  the  soundness  of  the  materials  which  enter  into 
the  construction  of  drains,  the  hydraulic  test  is  a  reliable  one, 
but  it  is  incomplete  by  itself,  as  it  fails  to  indicate  whether  a 
trap  has  a  water  seal  or  not. 

It  is  sometimes  contended  that  the  hydraulic  test  is  too 
severe  for  earthenware  drains,  and  that  it  subjects  them  to 
varying  degrees  of  strain  on  account  of  its  varying  head.  If, 
however,  the  actual  pressure  which  is  necessary  to  burst  an 


230     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

earthenware  pipe  is  compared  with  that  due  to  7 -feet  head  of 
water,  it  is  very  difficult  to  see  where  the  severity  of  the 
hydraulic  test  comes  in ;  further,  as  any  drain  is  liable  to  be 
choked  by  foreign  matter  getting  into  it,  the  damming  back  of 
the  water  subjects  the  drain  to  a  similar  test.  The  argument 
against  the  hydraulic  test  that  unequal  strain,  which  is  the 
result  of  varying  internal  pressures,  has  an  ill  effect  upon  a 
drain  is  absurd,  especially  when  the  maximum  strain  is  so 
comparatively  small.  Unequal  strains,  however,  which  have 
a  destructive  effect  upon  earthenware  pipes  are  those  due 
to  external  forces,  which  are  principally  caused  by  unequal 
settlement  of  the  ground. 

Air  Tests. — To  apply  the  air  test  to  drains,  all  that  is 
necessary  is  to  stop  up  all  open  ends,  and  to  force  in  air  at  any 
point  by  means  of  a  pump  or  bellows ;  the  air  pressure  may  be 
recorded  on  a  simple  form  of  water  gauge,  or  upon  a  spring  coil 
gauge,  the  type  of  gauge  depending  upon  the  extent  of  the 
pressure  desired. 

Where  traps  are  connected  with  a  system  to  be  tested,  the 
air  pressure  is  usually  controlled  by  the  water  seals  of  the 
traps,  and  generally  not  more  than  1  inch  of  water  pressure 
can  be  applied.  Where  traps  are  absent  or  plugged,  any  desired 
safe  pressure  may  be  applied,  but  as  a  rule  a  pressure  of  not 
more  than  3  Ib.  per  sq.  inch  is  necessary  on  account  of  the 
searching  nature  of  this  test. 

So  far  as  testing  is  concerned,  both  for  the  soundness  of  a 
system  and  for  the  pressure  resistance  of  the  seal  of  a  trap,  the 
air  test  is  a  very  good  one,  and  one  that  is  easily  applied. 
Instead  of  using  a  spring  coil  gauge  for  recording  higher 
pressures,  the  ordinary  water  gauge  will  suffice  if  mercury  is 
substituted  for  water.  Tf  a  system  is  faulty  it  is  readily 
indicated  by  the  gauge. 

The  chief  difficulty  which  is  associated  with  the  air  test  is 
in  the  discovery  of  a  leakage  when  one  exists,  and  the  smaller 
the  defect  the  more  troublesome  it  is  to  find.  This  drawback, 
however,  may  be  overcome  to  a  great  extent  by  first  dividing 
a  system  into  a  number  of  parts,  and  ascertaining  the  section 
in  which  the  defect  exits.  Srnoke  may  afterwards  be  forced 
through  the  section  to  aid  in  locating  the  defective  point. 


DRAINAGE    OF    HOUSES    AND    OTHER    BUILDINGS       231 

An  air  test  is  far  more  searching  than  a  hydraulic  test, 
although  the  former  may  be  applied  at  a  much  lower  pressure, 
as  air  will  pass  through  small  interstices,  where  water  would 
simply  clog  them  up. 

Smoke  Test. — This  test  is  widely  adopted,  but  it  is  often 
applied  in  a  very  perfunctory  manner.  There  are  two  methods 
of  smoke  testing,  viz. :  by  the  use  of  smoke  rockets,  and  by 
forcing  smoke  into  drains  or  other  pipes  with  the  aid  of  a 
machine. 

The  smoke  test  is  carried  out  by  introducing  smoke  at  the 
lowest  end  of  a  system  of  pipes,  and  when  all  air  is  dislodged 
the  outlets  at  the  higher  levels  are  then  plugged.  For  a  final 
test  the  smoke  test  is  not  one  of  the  best ;  the  condition  of  a 
drain  with  regard  to  its  dryness  or  wetness  very  materially 
affects  the  test,  and  if  no  smoke  is  found  to  issue  at  any 
point  from  a  drain,  that  may  be  no  guarantee  that  such  a 
drain  is  free  from  defects. 

When  smoke  testing  is  adopted  for  drains  that  are  buried 
in  the  ground,  the  latter  is  sometimes  pierced  with  a  long  steel 
spear  in  the  immediate  neighbourhood  of  the  drains,  so  as  to 
provide  a  means  of  escape  for  smoke  if  a  defect  exists. 

Smoke  rockets  are  not  suitable  for  final  tests  on  account  of 
the  limited  volume  of  smoke  they  produce,  and  neither  can  any 
pressure  be  generated  with  rockets.  For  a  preliminary  test 
smoke  rockets  are  sometimes  useful,  and  they  may  also  be  of 
service  in  locating  a  leakage  when  one  is  known  to  exist. 

Smell  Test. — The  modern  method  of  applying  a  smell  test 
is  to  flush  through  the  trap  of  a  w.c.  or  through  a  gully  a 
sealed  tube  which  contains  some  strong  smelling  compound ; 
the  tube  or  "grenade,"  as  it  is  often  termed,  takes  different 
forms,  but  all  are  arranged  that  their  contents  may  be  dis- 
charged into  drains,  and  the  odour  detected  by  the  sense  of 
smell  if  a  defect  exists.  A  smell  test  may  sometimes  be  used 
as  a  preliminary  one,  but  as  it  is  not  a  positive  test  it  is 
un suited  for  final  testing. 

Remarks. — Generally  speaking,  for  iron  drains  the 
most  suitable  form  of  testing  is  by  the  use  of  air ;  earthenware 
drains  are  better  tested  with  both  the  hydraulic  and  smoke 
tests,  as  these  will  seldom  withstand  an  air  test.  The  best 


232     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

results  can  be  obtained  by  smoke  testing  when  no  water  is 
flowing  through  a  drain,  and  when  its  inner  surfaces  are  dry. 
For  testing  pipes  above  ground  level,  such  as  waste  and  soil 
pipes,  either  the  air  or  smoke  test  may  be  used,  but  the  former 
is  the  better  of  the  two. 


FIG.  162. — At  A  the  "  Addison  "  stopper  is  shown,  and  B  gives 
a  bag  stopper  by  Nicholls  and  Clarke. 

Testing  Appliances. — For  stopping  either  the  inlets  or 
outlets  of  drains  and  of  other  pipes,  expanding  plugs  and 
rubber  or  canvas  bags  are  used.  At  A,  Fig.  162,  the  "  Addison  " 
stopper  is  shown,  where  a  rubber  ring  is  expanded  between 
two  galvanised  iron  discs  by  means  of  the  wing  nut  n ;  this 


DRAINAGE    OF    HOUSES    AND    OTHER    BUILDINGS       233 


stopper  is  formed  at  C  on  the  cup  leather  principle,  so  that 
internal  pressure  may  aid  in  making  a  tight  joint.  The 
central  tube  on  which  the  wing-nut  is  screwed  serves  as  a 
means  for  the  escape  of  water  prior  to  the  removal  of  the 
stopper,  when  the  hydraulic  test  is  applied  ;  it  also  admits  of  a 
connection  being  made  with  a  smoke  machine  for  testing 
purposes. 

There  are  various  forms  of  expanding  stoppers,  and 
although  similar  in  principle  they  differ  a  little  in  some 
details. 

A  bag  stopper  B,  Fig.  162,  is  made  both  in  cylindrical  and 


J 


L 


FIG.  163. — Smoke  producing  machine. 

globular  forms,  but  the  latter  is  not  so  good  as  the  one  shown, 
owing  to  its  having  a  much  smaller  bearing  surface.  Bag 
stoppers  are  inflated  after  being  placed  in  position  by  means 
of  an  air-pump,  and  they  are  provided  with  stop-cocks  to  retain 
the  air  in  them. 

The  chief  advantage  of  bag  stoppers  is  their  lightness,  and 
one  stopper  may  be  used  for  testing  pipes  from  4  to  9  inches 
diameter. 

Smoke  testing  machines  take  various  forms,  a  simple 
type  being  given  in  Fig.  163.  The  sides  of  the  machine  are 
water  jacketed,  and  along  with  the  cover  or  dome  D  form  a 
seal  to  prevent  the  escape  of  smoke  when  a  drain  is  being 


234     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


Fra.  164.— Smoke  rocket. 


tested.  When  the  cover  is  raised  air  flows  through  the  inlet 
A  to  fill  the  space,  a  non-return  valve  V  being  arranged  to 
prevent  smoke  returning  from  the  drain.  A  volume  of  smoke 

is  displaced  when  the 
cover  is  pushed  down, 
a  flap  or  other  form  of 
valve  at  F  being  pro- 
vided to  prevent  smoke 
escaping  through  that 
channel.  In  the  body 

of  the  machine  any  suitable  smoke  producing  material,  such  as 
brown  paper,  rag,  or  cotton  waste,  and  which  has  first  been 
steeped  in  creosote  oil,  may  be  used.  To  prevent  water  getting 

into  the  machine  when 
the    latter   is   in   use, 
the  outer  casing  should 
be  lower  than  the  inner 
lining,  as  in  Fig.  163. 
A  flexible  tube  is  used 
to  connect  the  machine 
with  the  drain  or  pipe 
to  be  tested,  the  sound- 
ness of  the  latter  being 
indicated  by  the  mov- 
able   cover   D,   which 
will  be  held  up  by  the 
internal    pressure     or 
fall  as  the  case  may  be. 
In  Fig.  164  a 
smoke    rocket    is 
shown    with    two 
pieces  of  lath  at- 
tached to  keep  it 
above  the  invert  of 
a  drain.     Rockets 

when  lighted  produce  dense  volumes  of  smoke,  and  two  or 
more  may  be  used  at  one  time. 

A  gauge  in  its  simplest  form  for  air  testing  is  given  in 
Fig.  165.     It  may  be  placed  in  any  convenient  position  when 


AIR  PUMP. 

FIG.  165. — Gauge  and  air  pump. 


DRAINAGE   OF   HOUSES    AND   OTHER   BUILDINGS       235 


joined  with  the  air  delivery  tube  from  the  pump.  To 
read  the  pressure  on  the  gauge,  a  graduated  piece  of 
stiff  white  paper  or  thin  cardboard  may  be  fixed  to  a 
wooden  frame,  or  the  latter  may  be  prepared  and  graduated 
instead. 

Fig.  166  gives  Banner's  grenade,  which  is  made  of  thin 
glass,  and  filled  with 
a  strong  -  smelling 
chemical  substance. 
These  grenades  are 
only  about  2  inches 

J  FIG.  166. — Banner  s  grenade. 

long,  so  that  a   few 

may  readily  be  carried  in  a  waistcoat  pocket.  To  float  a 
grenade  through  a  trap,  the  former  may  be  fixed  to  a  hard 
wooden  ball  of  about  2J  inches  diameter  as  in  Fig.  167 ;  this  is 
known  as  Banner's  "  Explorer,"  and  to  it  is  attached  a  length 
of  cord  to  enable  it  to  be  withdrawn  from  the  drain.  When 
the  ball  has  been  passed  to  the  desired  point,  the  grenade  is 

broken  by  the  aid  of  a  spring  upon 
giving  the  cord  a  sudden  jerk. 

Other  forms  of  chemical  testers 
are  used,  but  they  chiefly  differ 
from  the  above  in  the  manner  their 
contents  are  discharged. 

Discharging  Capacity  of  Drains. 
— Although  much  progress  has  been 
made  in  the  design  of  drainage 
work,  drains  are  still  often  laid  that 
are  far  too  large  for  their  purpose. 
Frequently  it  is  found  9-inch  pipes 
are  used  where  those  of  5  or  6 
inches  diameter  would  be  more 
suitable,  and  6 -inch  drains  where 
4-inch  pipes  would  suffice. 

Where  practicable,  drains  should  be  laid  with  gradients 
which  will  give  the  discharging  matter  a  minimum  velocity 
of  3  feet  per  second,  in  order  that  they  may  be  self -cleansing. 
The  conditions  upon  which  the  velocity  of  discharge  chiefly 
depend  are :  gradients  of  drains,  size  of  drains,  number  and 


FIG.  167. — Banner's  explorer. 


236      DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 

kind  of   bends  used,  depth  of  flowing  liquid,  and  the  initial 
velocity  of  the  entering  water. 

The  effect  of  the  gradient  of  a  drain  upon  the  velocity  is 
proportional  to  the  square  root  of  the  sine  of  the  gradient, 
the  value  of  the  sine  being  obtained  by  dividing  the  vertical 


131 

A  B 

FIG.  168. — Diagram  illustrating  hydraulic  mean  depth. 

fall  by  the  length  of  the  drain  under  consideration.     Thus,  if 
a  length  of  drain  is  75  feet,  and  has  a  vertical  drop  between 

the  two  ends  of  1  ft.  6  in.,  the  sine  of  the  gradient  =  — 1  =  -02. 

75 

Size  of  drain  and  depth  of  flow  influence  what  is  termed 
the  hydraulic  mean  depth,  and  the  velocity  of  flow  is  pro- 
portional also  to  the  square  root  of  this  value. 

Hydraulic  Mean  Depth. — At  A, 
Fig.  168,  a  pipe  is  represented  as 
flowing  half  full.  If  we  assume  that  the 
semicircular  section  Imn  could  be  cut 
or  bent  so  as  to  form  a  rectangular 
channel  B,  Fig.  168,  whose  width  is 
equal  to  the  wetted  surface  Inm,  then 
instead  of  having  varying  depth  from 
the  water  surface  we  should  have  a 
uniform  depth  r  as  in  the  rectangular 

channel.  The  depth  r  would  be  the  hydraulic  mean  depth 
required,  and  this  is  obtained  by  dividing  the  sectional  area 
of  the  flow  by  the  wetted  surface  of  the  pipe.  When  a  drain 
is  flowing  full,  or  half  full,  its  hydraulic  mean  depth  may  be 
found  by  simply  dividing  the  diameter  in  feet  by  4. 

To   obtain   the  hydraulic  mean   depth  when    drains    are 


DRAINAGE   OF   HOUSES    AND    OTHER   BUILDINGS       237 

flowing  other  than  full  or  half  full,  and  when  a  student  has 
no  knowledge  of  trigonometry,  the  following  method  may  be 
used.  Let  Fig.  169  represent  a  drain  flowing  less  than  half 
full.  Now,  before  the  area  abc  can  be  found  the  length  of 
chord  ab  must  be  ascertained,  either  by  measurement  from  a 
drawing  or  by  calculation. 

The  following  formula  may  be  used  for  calculating  the 
chord  ab,  when  the  depth  of  flow  and  the  diameter  of  the 
drain  are  known : — 

Chord  ab  =  2 Vh  x(D-h)         -         -  .         .     (1) 

Where  h  =  depth  of  flow  in  feet. 
„     D  =  diameter  of  drain  in  feet. 

The  area  of  segment  abc,  Fig.  169, 


and  the  wetted  surface  acb,  Fig.  169, 

=  •01745  x^xR.        ...  .     (3) 

Where  &  —  number  of  degrees  in  segment 

„      R  =  radius  of  circle 

The  number  of  degrees  in  segment  may  be  obtained  by  the 
aid  of  a  protractor  after  drawing  the  pipe  full  size  or  to  a 
large  scale. 

Another  method  of  obtaining  the  wetted  perimeter  or 
surface  acb,  Fig.  169,  is  by  the  following  rule  : — 

T  -,      Sac  —  ab 

Length  of  arc  acb  = — (4) 

o 

and  the  length  of  a  straight  line  ac 

(5) 


If  the  depth  of  flow  exceeds  half  the  diameter  of  a  drain, 
its  area  may  be  obtained  by  finding  the  area  of  the  upper 
segmental  part  and  deducting  it  from  the  area  of  the  whole 
circle. 

In  like  manner  the  wetted  perimeter  may  be  determined 
when  a  drain  is  flowing  more  than  half  full  by  first  obtaining 
the  length  of  the  unwetted  arc,  and  deducting  it  from  the 
circumference  of  the  pipe  which  is  being  considered. 


238     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

Example  1. — Determine  the  hydraulic  mean  depth  of  a 
6-inch  pipe  when  flowing  one  quarter  of  its  depth,  as  repre- 
sented by  Fig.  169. 

Before  the  sectional  area  of  dbc  can  be  found  the  length  of 
the  chord  ab  must  be  known.  The  depth  of  the  flow  h  when 
a  6-inch  drain  is  running  one  quarter  full  =  '125  feet. 


By  Formula  1,  ab  =  2Vh  x  (D-A). 


Substituting  values,  ab  =  2*/'l'2o  x  ('5  -125), 


.-.  oft  =  433  feet. 
From  Formula  2  the  sectional  area  of  dbc 

|m 


2xab' 


,    ,  .,    ,    -,     2  x  433  x  125.     125 
and  when  values  are  substituted  =  —  -  -f 


3  2  x  433 

'0023; 
/.  sectional  area  qfo  =  -Q384  sq.  feet. 

The  length  of  the  wetted  perimeter  may  be  found  by 
Formula  4,  but  before  this  rule  can  be  applied  the  straight  line 
ac,  Fig.  169,  must  be  known. 


By  Formula  5,  ac  =  V(^ab)2  +  A2. 


Substituting  values,  oc  =  V(Jx  433)2+1252, 


.-.  length,  ac  =  -25  feet. 

Formula  4  may  now  be  applied,  where 

7     Sac  —  ab 
acb  = — . 

,     (8  x -25)- -433     1-567 
Substituting  values,  acb  =  5> —    — ^—      -  =  — - —  ; 

O  *J 

:.  wetted  surface  acb  =  '522  feet. 

As  the  hydraulic  mean  depth  r  is  found  by  dividing  the 
area  of  flow  by  the  wetted  surface, 


then  r  =  = -0735  feet. 


DRAINAGE   OF   HOUSES   AND    OTHER    BUILDINGS      239 

To  facilitate  calculations  being  made  in  connection  with 
drainage  work,  the  following  table  is  given  : — 


TABLE  III. 

DATA  FOR  OBTAINING  HYDRAULIC  MEAN  DEPTH,  AND  THE 
SECTIONAL  AREA  OF  FLOW  IN  CIRCULAR  DRAIN  PIPES,  WITH 
WATER  FLOWING  AT  DIFFERENT  DEPTHS. 


Depth  of  flow. 

Hydraulic  mean  depth 
r. 

Sectional  area  of 
flow. 

Full 

Dx  -25 

D2  x  7854 

i   „ 

D  x  -296 

D2  x  -632 

D  x  -292 

D2  x  -556 

Dx  -25 

D2  x  -393 

Dx-186 

D2  x  -229 

i     „ 

Dx-147 

'D2x-154 

D= diameter  of  drain  in  feet. 

Bends  and  changes  of  direction  retard  the  velocity  of  flow 
to  a  great  extent,  and  the  quicker  a  bend  the  greater  the 
resistance  offered.  When  open  channel  bends  are  used  which 
permit  of  a  discharge  splashing  over  them,  the  velocity  will 
be  further  retarded  by  them. 

Smoothness  or  roughness  of  a  surface  also  has  its  effect, 
and  it  is  fairly  obvious  the  smoother  a  pipe  surface,  other 
conditions  being  equal,  the  smaller  frictional  resistance 
will  be. 

Formulae  for  obtaining  the  velocity  of  discharge  through 
drains  are  very  numerous,  but  one  of  the  best  is  that  by 
Kutter. 

Where  v  —  c  Jr  x  s (6) 

„      v  =  velocity  in  feet  per  second. 
„      r  =  hydraulic  mean  depth  in  feet. 

s  =  sine  of  inclination  =  fall  •—  length. 
„      c  =  a   coefficient   which   varies   with    the    size   and 
condition  of  a  pipe. 


240     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


For  smooth  drain  pipes 


181+:00281 


1  + 


41-6  +  ™ 


•013  T 

\/r 


For  general  work  the  values  of  c  take  too  long  to  work  out 
by  the  formula  given,  but  by  the  aid  of  Table  IV.,  which  gives 
values  of  c  for  varying  depths  of  flow,  the  general  formula  is 
rendered  convenient. 

TABLE  IV. 


Diameter  of 
drain  in 
inches. 

Values  of  c  (calculated  by  the  writer). 

Depth  of  flow  in  drain. 

Full.                |  full. 

i  full.               i  full. 

| 

! 

8 
9 

66 
68 
71 
74 

77 
80 

68 

72 
75 
78 
81 
84 

66 
68 
71 
74 
77 
80 

54 
57 
60 
63 
66 
69 

It  will  be  observed,  upon  reference  to  Table  IV,  that  the 
values  of  c  increase  with  the  diameter  of  a  pipe,  and  are  highest 
when  a  drain  is  flowing  three-quarters  full  and  lowest  when 
running  only  one-quarter  full.  It  is  therefore  of  importance 
when  deciding  upon  a  suitable  gradient  that  attention  be  paid 
to  the  probable  normal  depth  of  flow. 

Example  2.  —  Find  the  gradients  which  will  give  a  velocity 
of  3  feet  per  second  in  a  6  -inch  drain  when  flowing  J  and  £ 
full  respectively. 

By  transposing  Formula  6  and  substituting  _  for  s  we  have 

/ 


Where  1  =  length  of  drain  in  feet. 

„      h  =  vertical  fall  in  feet  for  the  given  length. 
c,  r  and  v  as  before. 


DRAINAGE    OF    HOUSES    AND    OTHER    BUILDINGS       24 1 

Upon  reference  to  Table  III.  the  hydraulic  mean  depth 
r  =  "25  x  D  =  '25  x  *5  when  a  6-inch  drain  is  running  J  full,  and 
•147  x  D  =  147  x  '5  when  flowing  J  full.  The  values  of  c  from 
Table  IV.  for  the  same  depths  of  flow  in  a  6-inch  drain  are  71 
and  60  respectively. 

When  a  6 -inch  drain  is  flowing  J  full  the  length  of  drain 
per  foot  of  fall  to  give  a  velocity  of  3  feet  per  .second  is  found 
by  Formula  7. 

Where  l  =  c  X^x    . 

602x -5x147x1 
Substituting  values,  /  =  —        — 02 > 

7  _  3600  x -5x147. 
— q — 

.-.  Z  =  29-4,  or  say  30. 

And  gradient  necessary  for  a  6 -inch  drain  to  give  a  velocity  of 
3  feet  per  second  when  flowing  only  J  full  =  1  in  30. 
When  flowing  J  full 

1  = 


712  x  "5  x  '^5  x  1 
Substituting  values,  /  =  -  — , 

7_5041x-5x-25 
~9~     ~; 
/.  ?  =  70. 

For  this  case  the  necessary  gradient  will  be  1  in  70. 

The  calculations  clearly  show  to  what  extent  the  depth  of 
flow  has  upon  the  velocity  in  the  same  pipe,  and  a  com- 
paratively quick  gradient  is  necessary  when  a  6 -inch  drain 
only  flows  one  quarter  full.  For  short  drains  where  a  discharge 
enters  with  a  high  velocity,  rather  flatter  gradients  could  be 
used,  but  for  long  drains  the  formula  given  is  a  safe  one  to 
use. 

When  the  velocity  of  flow  has  been  determined,  the  dis- 
charging  capacity  of  a  drain  in  gallons  may  be  ascertained 
by  multiplying  the  sectional  area  of  flow  by  the  velocity  and 
afterwards  by  6J.     Expressed  as  a  formula — 
16 


242      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

G  =  Ax^x6J (8) 

Where  G  =  gallons  discharged  per  second. 
„       A  =  sectional  area  of  flow  in  feet. 
„       v  =  velocity  in  feet  per  second. 
J}     6J  =  volume  in  gallons  equivalent  to  one  cubic  foot 
of  water. 

Example  3. — Find  the  discharge  in  gallons  per  minute  of  a 
6-inch  drain  when  flowing  f  full  and  when  laid  with  a 
gradient  of  1  in  50. 

By  Formula  6,  v  =  c  *Jr  x  s. 
The  value  of  s  =  1  -r  50  =  '02. 

From  Table  IV.  the  value  of  c  will  be  found  to  be  75,  and 
from  Table  III.  r  =  Dx -296. 
Substituting  values,  we  have 


'5  x  -296  x  -02. 


.*.  0  =  4'05,  ft.  per  second. 

The  discharging  capacity  of  the  drain  may  now  be  found 
by  Formula  8, 

where  G  =  A  x  v  X  6  J. 

In  Table  III.  the  sectional  area  of  flow  when  a  drain  is  | 
full  =  D2  x  '632,  and  for  a  6-inch  drain  =  '52  x  '632. 

Substituting  values  G  =  *52  x  '632  x  4'05  x  6  J  ; 

/.  G  =  3'999,  say  4  gallons  per  second, 
and  the  discharge  per  minute  =  4x60  =  240  gallons. 

For  general  work  the  gradients  given  in  the  following  table 
are  suitable  for  short  lengths  of  drains. 

TABLE  V.  . 

DIAMETER  DRAIN.  GRADIENTS. 

4  inch  branch  from  yard  gully  .        .     1  in  24  -  1  inch  in  2  ft. 
4  inch  main  drains   .         .         .  1  in  36  =  1       ,     in  3  ft. 


1  in  42  =  1 
1  in  48  =  1 
1  in  60  =  1 
1  in  78  =  1 
1  in  102  =  1 


in  3  ft.  6  in. 
in  4  ft. 
in  5  ft. 
in  6  ft.  6  in. 
in  8  ft.  6  in. 


CHAPTER   IX 

DISPOSAL  AND  TREATMENT  OF  SEWAGE  FROM 
MANSIONS   AND   HOUSES   IN   COUNTRY   DISTRICTS 

IN  rural  districts  it  is  often  necessary,  on  account  of  the 
absence  of  a  general  sewerage  system,  to  make  special  pro- 
vision for  the  treatment  and  disposal  of  the  sewage  from  large 
isolated  buildings,  or  from  a  group  of  small  dwellings. 

Different  methods  of  dealing  with  sewage  can  be  adopted, 
but  the  choice  of  a  system  largely  depends  upon  local  conditions 
and  the  amount  of  money  the  owner  of  a  property  is  prepared 
to  spend. 

The  following  methods  of  sewage  disposal  and  treatment 
are  in  general  use  for  small  or  private  works. 

1.  Cesspools   which    overflow   on   to   land   or   into    some 
available  stream. 

2.  Bacterial  systems  of  purification. 

(a)  Absorption  and  utilisation  of  sewage  by  means  of 

sub-irrigation,  and  with  or  without  preliminary 
treatment. 

(b)  Treatment  in  septic  tanks,  and  subsequent  treat- 

ment of  the  effluent  on  land. 

(c)  Treatment  in  septic  tanks,  and  the  subsequent 

passage   of   effluent   through   contact   beds  or 
percolating  filters. 

The  first  method  is  usually  a  very  unsatisfactory  one,  on 
account  of  the  nuisance  caused  when  emptying  cesspools,  the 
frequent  pollution  of  the  soil  and  underground  water  supplies 
by  defective  construction,  and  the  pollution  of  streams  by 
overflowing  sewage. 

Cesspools  always  possess  objectionable  features,  even  when 
soundly  constructed.  If  they  overflow  on  to  land  a  rank 

243 


244      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

grass  quickly  grows  on  the  area  dosed,  and  their  emptying  is 
frequently  delayed  on  account  of  the  objectionable  nature  of 
the  operation. 

When  cesspools  are  used  they  should  be  well  ventilated 
and  of  water-tight  construction ;  their  size  depends  upon  the 
daily  amount  of  sewage  they  are  likely  to  receive,  whether 
rain-water  is  admitted  into  them  or  not,  and  the  length  of 
time  before  emptying. 

Generally  speaking,  the  greater  volume  of  the  rain-water 
should  be  excluded  from  foul-water  drains  which  either  dis- 
charge into  a  cesspool,  or  into  a  tank  in  connection  with  a 
bacterial  system  of  sewage  treatment. 

In  a  bacterial  system  the  purification  of  the  sewage  is 
accomplished  by  minute  living  organisms,  which,  when  given 
suitable  conditions,  thrive,  and  carry  out  their  work.  The 
two  chief  classes  of  bacteria  which  are  responsible  for  the 
purification  of  sewage  are  aerobic  and  anaerobic ;  the  former 
require  a  liberal  supply  of  oxygen  for  their  development, 
whilst  the  latter  only  thrive  in  the  absence  of  oxygen. 

For  a  small  scheme  of  sewage  purification  to  be  a  success, 
it  must  be  of  simple  construction  and  automatic  in  action : 
for  if  frequent  attention  is  necessary  the  chances  are  that  a 
system  will  be  neglected,  and  sooner  or  later  it  will  result  in 
failure. 

The  simplest  and  most  effective  way  of  rendering  sewage 
innoxious,  and  to  purify  it,  is  by  passing  it  on  to  land  which  is 
of  a  good  loamy  nature.  In  the  upper  layers  of  earth  bacteria 
are  present  in  considerable  numbers,  and  these  attack  the 
sewage,  break  it  up  into  simple  and  harmless  constituents,  and 
in  a  form  that  may  readily  be  assimilated  by  plant  life.  On 
account  of  the  numerous  bacteria  which  are  present  in  the  upper 
earth,  the  latter  has  been  termed  the  "  living  earth,"  and  nearly 
all  the  purification  effected  by  a  soil  is  done  within  the  upper 
three  feet ;  below  this  depth  little  purification  is  effected  by  a 
soil,  and  a  depth  is  soon  reached  where  organisms  do  not 
appear  to  exist. 

System  of  Sub-Irrigation. — Under  favourable  conditions  a 
system  of  drains  may  be  arranged  so  as  to  distribute  sewage 
that  it  can  be  absorbed  by  a  given  area  of  land.  The  drains, 


DISPOSAL    AND    TREATMENT    OF    SEWAGE 


245 


however, 
should  be 
kept  as  near 
the  surface 
as  practic- 
able, and  the 
sewage  re- 
quires to  be 
discharged 

so  that  every  part  of  the 
prepared  area  receives  its 
quota  of  sewage.  In  order 
to  effect  uniform  distribu- 
tion of  sewage,  a  given 
volume  must  be  discharged 
at  one  time ;  this  method 
prevents  the  overdosing  of 
isolated  parts  of  an  area, 
and  allows  the  bacteria  to 
better  perform  their  work. 
A  simple  sub -irrigation 
scheme  of  sewage  treat- 
ment is  given  in  Fig.  170. 
It  consists  principally  of 
a  septic  tank  S,  a  dosing 
chamber  T,  and  a  number 
of  open-jointed  field  drains 
which  are  placed  a  certain 
distance  apart  on  one  or 
both  sides  of  a  main  dis- 
tributing pipe.  The  pur- 
pose of  the  septic  tank  is 
to  liquefy  as  far  as  possible 
the  organic  solids  in  the 
sewage,  in  order  that  the 
latter  will  be  in  a  better 
condition  for  percolating 
into  the  earth.  The  septic 
tank  is  shown  provided 


246      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

with  submerged  inlet  and  outlet,  and  a  wall  W  should  be 
constructed  near  the  inlet  of  the  tank  to  prevent  its  contents 
being  unnecessarily  disturbed  by  a  sudden  inrush  of  water. 
In  a  small  septic  tank  a  screen  may  be  also  arranged  at  the 
outgo  0,  to  prevent  undigested  solid  matter  passing  into  the 
dosing  tank  T. 

When  sewage  is  first  turned  into  a  septic  tank,  a  certain 
time  must  elapse  (largely  depending  upon  weather  conditions) 
before  the  tank  properly  performs  its  work ;  in  other  words, 
before  septic  conditions  arise.  A  septic  tank  when  once  in 
working  order  should  not  be  emptied,  but  provision  should 
be  made  for  removing  any  irreducible  matter  which  accumu- 
lates in  it. 

In  the  tank  T  a  plenum  automatic  siphon  is  shown  for 
discharging  its  contents  into  the  subsoil  drains;  any  other 
suitable  contrivance  may  be  used  for  the  purpose,  but  anything 
that  depends  upon  movable  parts  is  usually  more  liable  to 
get  out  of  order.  To  the  outgo  of  the  siphon  a  pipe  P  is 
joined,  which  serves  the  purpose  of  an  overflow  for  the  tank 
and  also  as  a  ventilation  pipe  for  the  field  drains. 

The  subsoil  drains  require  to  be  carefully  arranged,  and  a 
good  porous  soil  is  essential  if  the  system  is  to  be  a  success. 
The  main  subsoil  drain,  which  may  be  of  ordinary  4-inch 
pipes,  should  be  laid  level  and  not  deeper  than  1  foot  below 
the  surface  of  the  ground;  branches  should  be  arranged  as 
in  plan  Fig.  170,  that  each  may  receive  its  proper  volume  of 
sewage.  The  open  jointed  branch  drains  should  also  be  fixed 
level,  and  a  suitable  length  per  person  is  from  40  to  45  feet. 
The  distance  between  the  distributing  branches  should  be 
regulated  by  the  character  of  the  soil,  and  will  vary  from  2J 
to  5  feet. 

With  regard  to  the  sizes  of  the  septic  and  dosing  tanks, 
the  former  should  have  a  capacity  of  about  one  day's  flow  and 
the  latter  about  half  a  day's  flow  of  sewage.  To  a  great  extent 
the  capacity  of  the  dosing  chamber  should  be  governed  by  the 
capacity  of  the  subsoil  drains.  From  dwelling-houses  where 
modern  sanitary  conveniences  are  in  use  the  volume  of  sewage 
discharged  will  be  from  15  to  25  gallons  per  occupant  per 
day.  By  making  the  dosing  tank  fairly  large,  the  subsoil 


DISPOSAL   AND   TREATMENT   OF    SEWAGE  247 

drains  will  be  better  charged,  and  in  consequence  the  sewage 
will  be  better  distributed. 

Both  the  septic  and  the  dosing  tank  should  be  covered, 
as  the  heat  in  the  sewage  is  better  maintained  in  cold  weather, 
and  covered  tanks  may  be  placed  in  positions  where  open 
ones  would  be  objectionable. 

Should  it  be  found  desirable  to  locate  the  septic  tank, 
Fig.  170,  in  the  immediate  neighbourhood  of  a  building,  it 
may  be  advisable  to  dispense  with  the  disconnecting  trap  on 
the  drain,  and  to  ventilate  the  tank  by  means  of  a  soil  or 
other  ventilating  pipe.  A  layer  of  earth  should  also  be  placed 
upon  the  roof  of  the  tank,  that  any  escaping  gases  may  be 
deodorised  in  passing  through  it. 

In  certain  cases  a  system  of  subsoil  irrigation  may  be 
inapplicable,  and  it  may  be  necessary  to  adopt  artificial  filters 
for  the  final  treatment  of  the  tank  effluent. 

Sewage  filters  are  of  two  types,  one  being  termed  contact 
beds  and  the  other  percolating  filters;  the  filtering  medium, 
however,  is  the  same  in  each  type,  and  commonly  consists 
of  clinker,  coke,  or  other  material  which  provides  suitable 
surfaces  for  the  growth  of  bacteria.  These  filters  operate 
by  intercepting  the  larger  particles  of  suspended  matter  in 
the  sewage,  and  by  oxidising  the  organic  solids  by  the  action 
of  living  organisms ;  if  the  process  is  carried  far  enough  a 
clear  and  non-putrefactive  effluent  is  obtained. 

Contact  "beds  in  construction  differ  from  percolating  filters ; 
the  walls  of  the  former  require  to  be  water-tight,  and  the 
filtering  medium  varies  in  depth  from  2  ft.  6  in.  to  over  4  feet, 
according  to  the  fall  available.  The  walls  of  percolating  filters 
may  be  cheaply  formed,  as  water-tight  construction  is  not 
essential,  and  they  may  also  be  perforated  to  aid  the  aeration 
of  the  filtering  medium.  Percolating  filters  are  not  usually 
less  than  5  feet  deep,  and  an  increased  depth  produces  an 
effluent  of  greater  purity. 

In  either  form  of  bacterial  filter  the  bottom  requires  to 
be  arranged  that  it  can  be  effectively  drained,  the  effluent 
being  conducted  to  a  suitable  outlet.  For  the  construction 
of  a  filter  perforated  tiles  or  pipes  may  be  used  for  the  under- 
drains,  and  upon  these  a  layer  of  rough  material  should  be 


248     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


placed ;  the  body  of  the 
filter  may  be  composed 
of  material  which  is  of 
a  fairly  uniform  size,  say 
J  inch  to  J  inch,  with  all 
dust  screened  out. 

When  contact  beds 
are  used,  the  sewage 
after  passing  through  the 
septic  tank  is  distributed 
over  the  surface  of  a 
bed,  and  when  the  latter 
is  full  the  sewage  is 
allowed  to  remain  in 
contact  with  the  material 
for  a  period  of  about  2 
hours,  whilst  the  bacteria 
effect  a  certain  amount 
of  purification.  After  the 
contact  period  the  efflu- 
ent is  discharged,  and 
the  bed  remains  empty 
for  any  period  from  say 
4  to  about  8  hours,  in 
order  that  it  may  be 
thoroughly  aerated. 

With  percolating 
filters  the  sewage  is  not 
retained  as  in  contact 
beds,  but  after  being 
evenly  distributed  over 
the  surface  of  the  filter 
the  sewage  trickles  down 
and  through  the  mass 
of  material,  and  freely 
escapes  at  the  outlet. 

The  volume  of  sewage 
with  which  a  contact  bed 
is  capable  of  dealing 


DISPOSAL    AND    TREATMENT    OF    SEWAGE  249 

varies   from  15  to  about   20   gallons   per   sq.   foot   per   day, 
according  to  the  strength  of  the  sewage. 

With  percolating  filters  their  rate  of  working  depends 
largely  upon  their  depth,  and  the  character  of  the  sewage; 
the  volume  of  sewage  filtered  varies  from  18  to  36  gallons 
per  sq.  foot  per  day.  When  either  a  contact  bed  or  a 
percolating  filter  yields  an  effluent  of  insufficient  purity, 
further  purification  by  secondary  beds  may  be  adopted. 

Where  adequate  fall  is  available,  a  small  purification  works 
similar  to  Fig.  171  may  be  constructed,  which  consist  of  a 
detritus  tank  T,  septic  tank  S,  automatic  dosing  tank  A, 
and  primary  and  secondary  filters.  The  house  drain  D  is 
shown  discharging  into  the  detritus  tank,  which  intercepts 
any  mineral  matter  that  may  pass  from  a  yard  or  other  surface 
into  the  drain.  From  the  detritus  tank  the  sewage  flows  into 
the  septic  tank,  where  anaerobic  organisms  attack  and  break 
up  the  solid  organic  matter.  The  effluent  from  the  septic 
tank  flows  into  the  automatic  dosing  tank  A,  which  regulates 
the  discharge  and  enables  every  part  of  the  primary  filter  to 
be  properly  dosed  with  sewage;  the  interval  between  the 
periods  of  discharge  also  allows  the  filter  to  receive  the 
necessary  supply  of  oxygen  for  the  development  of  the  aerobic 
organisms.  From  a  single  house  the  discharge  of  sewage  only 
takes  place  at  irregular  intervals,  and  unless  some  method  is 
adopted  for  regulating  the  discharge  the  filters  would  not  act 
satisfactorily,  as  some  parts  would  be  overdosed  whilst  other 
parts  would  have  little  or  no  work  to  do. 

To  distribute  the  tank  effluent  over  the  surface  of  a  filter 
various  methods  may  be  adopted,  but  in  Fig.  171  channels 
are  shown  which  are  supposed  to  be  notched  at  short  distances 
along  each  edge.  Fixed  jets  or  revolving  sprinklers  may,  under 
favourable  circumstances,  be  used  for  distributing  the  tank 
effluent,  but  the  small  orifices  of  jets  are  subject  to  chokage, 
and  revolving  sprinklers  are  usually  too  costly  for  a  small 
system  of  sewage  purification.  After  the  effluent  has  per- 
colated through  the  primary  filter,  it  passes  to  the  secondary 
filter,  and  thence  to  the  outlet  drain.  The  area  of  a  secondary 
filter  may  only  require  to  be  half  that  of  the  primary  filter, 
and  the  capacity  of  a  septic  tank  for  the  installation  shown 


Of   THE 

UNIVERSITY 


250     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

should  be  about  equal  to  one  and  a  half  day's  discharge.  The 
automatic  dosing  tank  for  regulating  the  discharge  may  have 
a  capacity  of  twenty  gallons  and  over,  depending  upon  the 
size  of  the  purification  works.  It  is  not  essential  that  a 
system  should  be  so  compact  as  that  in  Fig.  171,  and  the 
different  units  may  be  some  distance  apart  if  the  fall  of  the 
ground  should  favour  that  arrangement. 


CHAPTER   X 
WATER   SUPPLY 

IN  nature  there  is  no  water  which  is  absolutely  pure,  as  it 
readily  absorbs  gases,  and  dissolves  traces  of  many  substances 
with  which  it  comes  in  contact.  The  term  "pure"  is  only 
used  in  a  relative  sense,  and  in  general  pure  water  is  under- 
stood to  be  water  which  contains  nothing  which  is  likely  to 
have  any  prejudicial  effect  upon  those  who  consume  it. 

It  is  only  in  country  districts  where  the  average  student 
of  Sanitary  Engineering  is  directly  concerned  with  water  at 
its  source  of  supply,  for  in  urban  districts,  where  a  scheme 
of  water-supply  has  been  carried  out,  water  is  delivered 
by  a  system  of  iron  pipes,  and  is  available  in  the  various 
streets. 

Water  Pollution. — A  point  of  importance  is  to  deliver 
water  to  a  dwelling  without  in  any  way  impairing  its  quality 
and  rendering  it  injurious  to  health. 

Some  of  the  ways  in  which  water  may  be  polluted  are  as 
follows : — 

1.  At  its   source,    by  coming   in    contact    with   decaying 

animal  or  vegetable  matter. 

2.  Through  badly  constructed  storage   tanks  or  reservoirs, 

or  by  polluting  matter  being  washed  into  them. 

3.  In  a  main  distributing  system. 

4.  By  the  materials  of  which  service  pipes  are  made. 

5.  Storage  cisterns  in  houses. 

6.  Defective  arrangement  of  service  pipes. 

Well  waters  may  be  contaminated  by  sewage  or  by  polluted 
surface  water  gaining  access  to  them,  or  where  pumps  are 
provided  they  may  be  the  cause  of  the  well  water  being 
impaired.  Lead  pumps  and  suction  pipes  are  frequently  used 

231 


252     DOMESTIC    SANITARY    ENGINEERING   AND    PLUMBING 

in  country  districts,  but  where  a  water  has  any  appreciable 
effect  upon  lead,  iron  pumps  and  pipes  should  be  adopted. 
Surface  water  may  be  excluded  from  wells  by  having  them 
properly  covered,  and  by  building  the  lining  of  the  wells 
above  the  level  of  the  surrounding  ground.  The  lining  of  a 
well  for  the  greater  part  of  its  depth  should  be  of  water-tight 
construction,  in  order  that  water  may  be  unable  to  gain  access 
without  first  having  percolated  through  a  large  mass  of  earth. 
In  the  case  of  deep  wells  the  subsoil  water  should  be  excluded 
altogether. 

Where  a  supply  of  water  is  obtained  from  a  spring,  every 
precaution  should  be  taken  that  the  tank  or  reservoir  in 
which  the  water  is  stored  is  suitably  constructed,  favourably 
located,  and  that  the  water  channels  are  properly  protected 
from  possible  pollution. 

For  a  country  house  which  is  chiefly  dependent  upon 
the  rainfall  for  its  supply,  the  chief  forms  of  pollution  are 
due  to  the  collecting  surfaces,  by  the  accumulation  of 
vegetable  growths,  by  droppings  from  birds  (where  pigeons 
and  fowls  are  kept),  and  by  metallic  impurity.  Tiled  roofs 
are  very  susceptible  to  vegetable  growths,  and  do  not  make 
such  good  collecting  surfaces  as  slated  roofs.  Eoofs  which 
drain  into  lead  gutters  are  not  suitable  for  collecting  areas 
where  the  water  is  to  be  used  for  dietetic  purposes,  as  rain- 
water has  a  very  active  effect  upon  lead  and  dissolves  traces 
of  this  metal. 

With  regard  to  the  pollution  of  water  by  means  of  a 
distributing  system,  this  may  occur  under  favourable  con- 
ditions where  ball  hydrants  are  in  use.  If,  for  example, 
polluting  matter  has  gained  access  to  a  ball  hydrant  which  is 
located  at  a  high  level,  and  the  water  is  temporarily  turned  off, 
or  is  drawn  from  the  higher  level  by  an  abnormal  draught  at 
a  lower  point,  the  hydrant  may  open  and  allow  the  polluting 
matter  to  enter  and  pass  into  the  water  pipes. 

Coal-gas  from  a  leaky  main  in  the  immediate  neighbour- 
hood of  a  ball  hydrant  may  also  enter  a  water  main  in  a 
similar  manner  to  the  above,  for  when  water  is  withdrawn 
from  a  main  so  as  to  partially  empty  the  latter,  air  rushes  in 
to  take  its  place.  Should  coal-gas  or  other  gas  escape  near 


WATER    SUPPLY  253 

a  hydrant,  it  may  readily  xpass  into  a  water  main  under  the 
conditions  stated. 

Lead  service  pipes  allow  certain  waters  to  dissolve  traces 
of  the  metal,  and  this  form  of  impurity  when  taken  into  the 
human  system  acts  as  a  cumulative  poison.  When  lead  is 
dissolved  by  water,  lead  service  pipes  should  not  be  used,  that 
is  if  the  water  is  used  for  human  consumption  in  any  form. 

The  following  extract l  clearly  indicates  the  danger  of  the 
prolonged  use  of  water  containing  traces  of  lead  : — 

"  Acute  lead  poisoning,  as  manifested  by  lead  colic,  anaemia, 
paralysis,  epilepsy,  etc.,  is  rarely  met  with  as  a  result  of  the 
use  of  leaded  waters,  but  the  insidious  forms  of  plumbism,  or 
lead  poisoning,  which  are  much  more  common  than  the  acute 
cases,  are  constantly  with  us.  The  effects  produced  by  the 
small  amounts  of  lead  taken  into  the  system  are  rarely  so 
serious  as  to  cause  death,  and  for  this  reason  the  injurious 
results  of  the  long-continued  use  of  waters  so  polluted  are 
only  gradually  receiving  recognition. 

"  It  is  believed  by  those  who  are  lucky  enough  to  escape, 
that  the  risks  of  this  kind  of  poisoning  are  exaggerated.  The 
contrary  is  quite  the  case. 

"The  symptoms  of  chronic  lead  poisoning,  such,  for 
example,  as  are  liable  to  ensue  after  the  continuous  use  of 
water  containing  small  quantities  of  lead,  are  as  follows: 
The  symptoms  are  usually  slow  in  their  progress ;  there  is 
general  anaemia,  with  a  consequent  anaemic  pallor  of  the  skin ; 
there  is  often  constipation  and  indigestion ;  there  may  be  loss 
of  appetite,  an  unquenchable  thirst,  a  constant  unpleasant, 
metallic  taste  in  the  mouth,  and  a  foul  odour  of  the  breath." 

Waters  which  dissolve  lead  are  usually  those  which  contain 
little  or  no  carbonate  of  lime.  Waters  which  contain  lime 
carbonates  do  not  act  upon  lead,  owing  to  a  protective  coating 
being  formed  on  the  surfaces  of  the  metal.  Soft  waters  as  a 
general  rule  dissolve  lead,  but  of  these  there  are  exceptions. 
For  example,  Loch  Katrine  water,  which  is  used  in  Glasgow, 
is  very  soft,  and  although  it  has  an  appreciable  effect  upon 
new  lead  pipes,  after  a  short  time  their  inner  surfaces  become 
coated  with  a  film  of  vegetable  matter,  which  combines  with 

1  New  Hampshire  Sanitary  Bulletin. 


254     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

the  oxide  of  lead  that  is  first  formed  and  prevents  further 
action  taking  place.  The  soft  water  from  Thirlmere,  which 
supplies  Manchester,  appears  to  have  a  similar  effect  on  lead 
pipes  as  that  from  Loch  Katrine. 

In  many  districts  storage  cisterns  require  to  be  fixed  in 
buildings  where  the  pressure  in  the  water  mains  falls  too  low 
to  give  a  constant  supply  throughout  the  whole  of  a  day,  and 
unless  such  cisterns  are  formed  of  suitable  material,  are 
properly  protected  and  suitably  placed,  contamination  of  the 
water  will  be  the  result.  All  storage  cisterns  should  be 
provided  with  covers,  to  exclude  foreign  matter  from  gaining 
access  to  them. 

Pollution  of  a  water  supply  by  defective  arrangement  of 
service  pipes  is  not  very  common  at  the  present  time,  owing 
largely  to  the  regulations  imposed  by  water  companies. 
In  country  districts  where  water  is  obtained  from  a  private 
source  irregular  connections  with  service  pipes  may  still  be 
found ;  such,  for  example,  as  the  direct  connection  of  a  service 
pipe  with  a  urinal  or  a  w.c.,  instead  of  the  direct  connection 
being  broken  by  means  of  a  flushing  cistern. 

Sources  of  Water  Supply. — The  principal  sources  of 
water  supply  for  rural  districts  are  Rain-water,  Springs,  and 
Wells;  whilst  Upland  surface  water  and  Eiver  water  are 
frequently  resorted  to  for  supplying  large  communities. 
These,  of  course,  all  depend  upon  the  rainfall  for  their 
replenishment. 

Rain-water  is  the  purest  form  of  natural  water  when 
caught  in  country  districts  which  are  well  removed  from 
towns  and  industrial  centres.  Rain  is  naturally  distilled 
water,  being  slowly  evaporated  from  the  sea  and  from  water 
on  the  earth's  surface;  the  aqueous  vapour  rises  into  higher 
regions  to  form  clouds,  and  upon  condensation  again  falls 
in  the  form  of  rain  or  snow. 

In  falling  through  the  atmosphere  rain-water  absorbs  any 
gases  which  may  be  present,  and  this  accounts  for  the  pollution 
of  rain-water  when  caught  in  the  neighbourhood  of  industrial 
centres,  where  the  atmosphere  is  laden  with  impurities,  such 
as  particles  of  soot,  sulphurous  compounds,  etc.,  and  where 
it  falls  on  surfaces  which  also  intercept  polluting  matter. 


WATER    SUPPLY  255 

Rain  is  rich  in  oxygen,  and  this  has  the  effect  of  increasing 
its  solvent  powers.  Fresh  rain-water  has  a  flat,  insipid  taste, 
but  this  may  be  improved  by  filtration. 

For  a  house  in  a  country  district  stored  rain-water  may 
occasionally  be  the  principal  or  only  convenient  source  of 
supply.  When  this  is  the  case,  and  it  is  also  used  for  drinking 
purposes,  the  following  require  special  consideration  : — 

(a)  Suitability  and  sufficiency  of  collecting  area. 

(b)  Sufficient  storage. 

(c)  Suitable  filtering  arrangement. 

Collecting  Area. — The  surface  used  for  collecting  rain- 
water requires  to  be  kept  as  free  as  practicable  from  all 
polluting  influences,  and  no  rain-water  should  be  used  for 
dietetic  purposes  which  flows  through  lead  gutters.  Slated 
roofs  make  good  collecting  surfaces,  but  where  a  suitable  roof 
area  is  inadequate  to  yield  the  necessary  volume  of  water, 
specially  prepared  surfaces  are  essential.  When  roofs  are  the 
collecting  surfaces,  the  most  suitable  channels  or  receivers  are 
cast-iron  gutters  which  have  their  inner  surfaces  well  coated 
with  a  bituminous  paint  such  as  Dr.  Angus  Smith's  solution, 
or  other  leadless  coating.  The  interior  surfaces  of  cast-iron 
rain-water  pipes  should  be  protected  in  a  similar  manner, 
whilst  the  external  surfaces  of  either  pipes  or  gutters  may 
be  protected  with  lead  paint  of  any  particular  colour. 

Earthenware  drains  are  .the  most  suitable  channels  for 
conducting  rain-water  to  a  storage  tank  from  the  rain-water 
pipes. 

Special  Collecting  Areas  take  different  forms.  They 
may  be  raised  above  the  contiguous  ground  and  arranged 
to  fall  to  one  end,  being  rendered  practically  impervious  with 
a  covering  of  either  cement  or  asphalt.  At  the  lower  end 
of  a  prepared  surface  a  collecting  channel  may  be  arranged 
which  discharges  into  a  suitable  sump  to  intercept  leaves 
and  similar  matter.  Collecting  areas  may  also  be  arranged 
as  in  Fig.  172.  In  this  case  the  rain  falls  upon  a  grass 
surface,  percolates  through  say  a  foot  of  soil,  and  after- 
wards through  perforated  tiles  which  are  placed  upon  an 
impervious  floor.  Special  tiles  may  readily  be  obtained  which 
will  support  the  soil,  and  at  the  same  time  permit  of 


256     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


:'v?''t?'^ •••'• 

^•••::-:\ ._ ,:: 


•&tf**v 

fte&&&AA 


S 


adequate  under  drainage  between  the  tiles 
and  water-tight  floor,  which  should  be 
made  to  fall  towards  a  sump  at  any 
suitable  point.  The  collecting  area  in 
Fig.  172  takes  advantage  of  the  purifying 
effect  of  the  organisms  in  the  soil,  as 
explained  in  the  chapter  on  sewage  treat- 
ment, and  also  of  the  purifying  power  of 
grass. 

Where  a  collecting  area  requires  to  be 

excavated  and  prepared  as  in  Fig.  172,  it 

should  be  channelled  all  round,  the  bottom 

of    the   channels    being    lower    than   the 

53    floor  of  the  prepared  area ;  this  provision 

|    reduces   materially  the  chances   of  pollu- 

3     tion. 

• 

So  All  special  collecting  surfaces  should 
g  be  properly  protected  from  surface  pollu- 
'§  tion  by  fowls,  cattle,  etc.,  by  having  them 
%  surrounded  with  a  suitable  fence.  Stored 
g  rain-water  is  only  suitable,  of  course, 
3  where  the  atmosphere  is  comparatively 
^  pure,  as  in  most  country  districts. 
^  Conditions  affecting  Yield  by  a  Surface. 

<N  — The  water  yielded  by  a  collecting  area 
^  for  storage  purposes  will  depend  upon  the 
£  amount  of  rainfall,  the  nature  of  the  area, 
and  whether  the  whole  or  only  a  part  of 
the  available  rainfall  flows  to  the  storage 
tank.  Where  rain  falls  directly  upon  an 
impervious  surface  nearly  the  whole  of  it 
may  be  passed  to  storage,  but  if  the  first 
part  of  the  rain  which  washes  the  collect- 
ing surface  is  diverted  to  waste,  then  only 
a  portion  of  the  total  rainfall  is  available 
for  storage  purposes.  Showers  of  short 
duration  may  require  deducting  from  the 
total  rainfall  where  a  separator  is  used, 
as  the  latter  may  not  come  into  action. 


WATER   SUPPLY  257 

When  rain  falls  upon  a  surface  like  Fig.  172  a  certain  per- 
centage is  retained  by  the  soil. 

Rainfall. — The  rainfall  varies  greatly  in  different  parts 
of  a  country,  and  that  of  any  district  principally  depends 
upon  the  physical  conditions  of  surrounding  districts,  prevail- 
ing winds,  and  the  distance  from  the  sea. 

"  In  the  British  Isles x  the  wettest  districts  include 
portions  of  the  counties  of  Inverness  and  Argyll,  the  Lake 
District  of  England,  and  the  mountainous  parts  of  North 
Wales ;  the  annual  rainfall  of  these  districts  exceeds  80 
inches.  In  some  parts  of  the  flat  counties  of  Bedford,  Cam- 
bridge, Norfolk,  and  Lincoln,  the  rainfall  per  annum  is  under 
23  inches." 

"A  large  area  of  England,  and  all  the  more  important 
agricultural  districts  in  Scotland,  have  a  rainfall  under  30 
inches,  and  the  greater  part  of  England  and  nearly  the  half 
of  Scotland  have  a  rainfall  not  exceeding  40  inches;  in 
Ireland  it  is  only  in  isolated  parts  where  the  rainfall  is  less 
than  40  inches." 

When  the  rainfall  of  any  district  is  required,  local  records 
which  have  extended  over  a  period  of  years  should  be  obtained 
where  possible. 

So  far  as  the  rainfall  of  the  British  Isles  in  general  is  con- 
cerned, much  information  can  be  obtained  from  British  Rain- 
fall, by  G.  J.  Symons. 

Volume  of  Water  Available. — The  actual  losses  due  to 
evaporation,  absorption,  and  waste,  etc.,  cannot  readily  be 
ascertained  with  exactness,  and  approximate  values  are  used 
to  a  more  or  less  extent. 

The  volume  of  rain-water  available  for  storage  purposes 
will  roughly  be  as  follows : — 

(a)  From  roofs   and  other   impervious   surfaces  where   a 

separator  is  used,  70  per  cent. 

(b)  From  grass  surfaces,  as  in  Fig.  172,  65  per  cent. 

(c)  From  roofs,  and  similar  surfaces,  where  water  flows 

direct  to  storage,  90  per  cent. 

To  calculate  the  volume  of  water  yielded  by  a  surface, 
when  its  area  and  the  rainfall  are  known,  or  to  obtain  the  area 

1  Encyclopaedia  Brittanica,  9th  Edition. 
17 


258     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

of  surface  which  will  yield  a  given  volume  of  water,  the  follow- 
ing formulae  may  be  used  :  — 

Where  G  =  gallons  of  water  required. 

„       A  =  area  of  collecting  surface  in  sq.  feet. 

„        f=  rainfall  in  inches. 

For  conditions  represented  by  (a)  G  =  '37Ax  x/  .  .  .     (9) 


For  conditions  represented  by  (b)  G  =  '34xAx/  .  .  .  (11) 

'•'-.         '       ;         A=4</  •  •  -(12> 

For  conditions  represented  by  (c)  G  =  '47xAx/  .  .  .  (13) 


Example  4.  —  If  the  rainfall  of  a  certain  district  is  25  inches 
per  annum,  find  the  volume  of  water  which  is  available  for 
storage  when  the  total  collecting  surface  is  2400  sq.  feet. 

For  condition  (a)  G  =  -37  x  A  x/, 

G  =  -37x2400x25; 
/.  G  =  22,200  gallons. 

For  condition  (b)  G  =  '34xAx/, 

G  =  -34x2400x25; 
.-.  G  =  20,400  gallons. 

For  condition  (c)  G  =  47  x  A  x/, 

G  =  -47x  2400x25; 
/.  G  =  28,200  gallons. 

Example  5.  —  What  collecting  area  will  be  necessary  where 
the  rainfall  is  28  inches  in  order  to  yield  54,750  gallons  -per 
year? 

O 

For  condition  (a)  A  =  -~=  —  ^  , 

'61  X/ 

A=  5475° 


•37  x  28 ' 
/.  A  =  5285  sq.  feet  of  surface. 


WATER    SUPPLY  259 


For  condition  (b)  A  =  - 


For  condition  (c)  A  =  ; 
A 


34  x/' 
.       54750 

•34x28' 
/.  A  =  5751  sq.  feet  of  surface. 

G 


47  x/' 
54750 


47  x  28  ' 
/.  A  =  4160  sq.  feet  of  surface. 

Capacity  of  Storage  Tanks. — It  is  obvious  that  the  storage 
capacity  of  a  rain-water  tank  need  not  be  capable  of  accom- 
modating the  total  rainfall,  as  the  latter  is  distributed  over  the 
whole  of  a  year.  Under  ordinary  conditions,  when  entirely 
dependent  upon  the  rainfall  for  a  supply,  the  storage  capacity 
in  this  country  should  be  equal  to  about  80  to  120  days' 
supply,  according  to  whether  a  district  is  a  wet  or  a  dry  one. 
A  less  capacity  will,  of  course,  suffice  where  rain-water  can  be 
supplemented  by  water  from  another  source. 

Water  Consumption. — The  consumption  of  water  is  usually 
stated  in  gallons  per  head  of  a  population,  and  this  varies  con- 
siderably in  different  localities.  In  towns  the  consumption 
per  head  varies  from  20  to  about  60  gallons  per  day,  smaller 
towns,  as  a  rule,  consuming  less  per  head  than  the  larger 
towns.  In  rural  districts  the  consumption  per  head  varies  from 
less  than  9  to  about  20  gallons  per  day,  the  smaller  value  apply- 
ing when  w.c.'s  are  not  in  use. 

Size  of  Tanks. — For  obtaining  the  size  of  a  rectangular 
tank  the  following  formulae  may  be  used : — 

Let  P  =  number  of  persons  for  which  storage  is  provided. 

„    C  =  gallons  allowed  per  head  per  day. 

„    S  =  number  of  days'  storage. 

„    I  =  length  of  tank  in  feet. 

„    &  =  breadth  of  tank  in  feet. 

„    h  =  depth  of  tank  in  feet. 

P  X  C  X  b 


260     DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 

.PxCxS 
-no*6j    '  •   (16) 

x.PxCxS 

-^&3T6i 

Example  6.  —  Determine  the  width  of  a  storage  tank  which 
is  21  ft.  6  in.  long,  and  8  feet  deep  below  the  overflow,  to  hold 
80  days'  supply  for  12  persons,  where  the  rate  of  consumption 
is  15  gallons  per  head  per  day. 

_.        -„  ,        i  n       -L 

By  Formula  16,  ^ 

'   ,     12x15x80 
Substituting  values,  b  = 

, 


~          , 
2x12x15x80x4 


43x8x25 
/.  6  =  13H  ft-,  say  18  ft.  5  in.  broad. 

Should  a  circular  tank  be  constructed,  the  formula  for 
calculating  its  diameter  or  depth  may  be  expressed  as  shown 
below. 

,     PxCxS 


/ 

V 


PxCxS 


Where  D  =  diameter  in  feet,  and  h,  P,  C  and  S  as  before. 

Example  7.  —  If  storage  is  provided  for  20  persons  for 
60  days,  what  depth  of  tank  will  be  essential,  if  its  diameter 
is  fixed  at  20  feet,  and  the  rate  of  consumption  at  12  gallons 
per  head  per  day  ? 

Formula  18  gives  h 
Substituting  values,  A^ 


.-.  h  =  7U  ft.,  say  7  ft.  4  in.  deep. 

Example  8.  —  Assuming  the  depth  of  the  tank  had  been 
fixed  at  9  ft.  6  in.  below  the  overflow,  and  the  diameter  of 
tank  was  required. 


WATER   SUPPLY  261 


Then  by  Formula  19,  D  =  .  /PxCxS 

V     Ax6j   ' 

and  substituting  values,  D  =    / 

v 


20  '  *  12 


/.  D  =  17-58  ft.,  say  17  ft.  7  in.  diameter. 

Purification  of  Rain  -  Water.  —  To  render  rain  -  water 
sufficiently  pure  for  drinking  purposes,  and  also  to  improve 
its  taste,  it  requires  to  be  filtered.  On  the  other  hand,  if  rain- 
water is  only  stored  for  general  household  use,  and  also  to 


PURE 


FOUL 

FIG.  173. — Roberts'  rain-water  separator. 

supply    sanitary    fittings,   a    high    degree   of    purity   is   not 
essential,  and  simple  straining  may  be  all  that  is  required. 

Rain-Water  Separators. — A  useful  appliance  for  preventing 
the  first  portion  of  a  rainfall  from  entering  a  storage  tank 
is  a  rain-water  separator  Fig.  173  (Roberts'),  which  can  be 
fixed  at  any  suitable  point  in  a  drain  leading  to  the  storage 
tank.  The  rain-water  separator  shown  is  self-acting,  and 
simply  diverts  to  waste  the  first  portion  of  the  rain  which 
contains  the  greater  portion  of  the  impurities  which  have 
accumulated  on  the  collecting  area.  Its  action  is  dependent 
upon  a  canting  or  tipping  compartment,  which  is  regulated 
to  fill  at  a  given  rate.  When  the  canter  is  up  or  in  its 
normal  position,  the  rain-water  flows  through  the  lower  or 


262     DOMESTIC    SANITARY    ENGINEERING    AND   PLUMBING 


foul-water  outlet ;  but  if  the  canter  is  full  of  water  it  tilts 
downwards  and  diverts  the  entering  water  through  the 
upper  outlet;  the  interval  required  for  filling  the  canter  is 
the  time  allowed  for  washing  the  collecting  surface.  The 
canter  is  emptied  by  means  of  a  siphon,  when  it  tilts  back  to 

its  former  position  some  time 
after  the  rain  has  continued 
to  fall.  If  a  shower  of  rain 
is  only  of  short  duration  and 
light,  the  canter  will  not 
come  into  action,  but  the 
whole  of  this  water  will  flow 
to  waste.  Separators  are 
made  in  a  number  of  sizes, 
to  suit  either  small  or  large 
collecting  areas,  and  for 
either  town  or  country  use. 

Another  form  of  Eoberts' 
separator  is  shown  by  Fig. 
174,  for  fixing  in  conjunction 
with  a  stack  of  pipes  so  as 
to  deliver  the  rain-water 
either  above  or  below  ground 
level.  The  vertical  type 
Fig.  174,  which  is  shown 
in  section,  contains  the 
following  principal  parts. 
Beginning  at  the  top,  A 
denotes  movable  strainers, 
and  B  a  perforated  slide 
which  regulates  the  How  of 
water  to  the  canter.  The 
small  chamber  at  C  contains  a  sluice  which  can  be  adjusted 
to  suit  the  area  of  collecting  surface.  E  shows  the  course 
taken  by  the  water  when  flowing  through  the  separator,  and 
J  represents  the  canting  chamber  which  revolves  for  a  limited 
distance  on  a  pivot  ra.  The  small  compartment  F  in  the  canter 
is  provided  with  a  small  regulated  outlet  G,  which  discharges 
into  the  lower  part  of  the  separator.  A  siphon  L  has  its 


PURE 

FIG.  174. — Roberts'  rain-water 
separator. 


WATER   SUPPLY  263 

outlet  leg  in  chamber  F,  whilst  its  inlet  leg  is  turned  into 
the  large  chamber  J.  The  lower  portion  of  the  separator  is 
divided  into  two  parts,  N  and  0,  by  a  thin  plate,  in  order  that 
the  canting  chamber  may  divert  the  water  on  either  side  of 
the  plate  according  to  the  relative  position  of  the  canter. 

Its  action  is  as  follows  :  When  water  enters  the  separator, 
a  portion  of  it  passes  through  the  strainers  A,  and  into  small 
upper  chamber  C,  from  which  it  flows  through  the  perforated 
slide  B  to  the  small  compartment  F ;  when  the  latter  is  full, 
water  overflows  into  the  main  body  of  the  canting  chamber  J, 
and  after  a  time  the  canter  turns  and  diverts  the  water  into 
chamber  0,  from  which  it  flows  to  storage.  Prior  to  canting 
the  water  is  delivered  into  chamber  N,  from  which  it  is  passed 
to  waste  as  in  Fig.  174.  The  small  chamber  F  is  slowly 
emptied  by  means  of  the  small  aperture  G,  and  as  the  level  of 
the  water  falls  the  siphon  is  brought  into  action,  when  the 
water  from  the  canting  chamber  is  also  discharged. 

To  ensure  these  separators  working  properly  they  require 
periodical  attention  to  keep  the  small  apertures  and  strainers 
clear,  and  also  to  lubricate  the  pivot  on  which  the  canter 
turns. 

When  a  more  simple  and  cheaper  appliance  is  required,  a 
spout  or  channel  might  suffice,  which  can  be  tilted  one  way 
or  the  other,  and  so  divert  the  water  either  to  storage  or  to 
waste. 

Sand  Filters. — A  well  constructed  sand  filter  is  a  very 
effective  type  for  dealing  with  large  volumes  of  rain-water. 
The  arrangement  of  storage  tank  and  filter  will  depend  to  a 
great  extent  upon  the  volume  to  be  filtered,  whether  they 
require  to  be  constructed  upon  sloping  or  upon  level  ground, 
and  whether  one  or  more  services  be  required.  If  it  is  assumed 
that  a  large  building  is  wholly  supplied  with  rain-water,  it 
would  not  be  necessary  to  filter  the  whole  of  the  water  if 
two  separate  services  were  adopted ;  viz.,  one  to  supply 
filtered  water  for  dietetic*  use,  and  the  other  unfiltered  water 
for  sanitary  fittings,  where  the  water  is  not  likely  to  be  used 
for  human  consumption,  and  for  laundry  purposes,  washing 
vehicles,  and  similar  uses. 

Bacteria  are   responsible  for  the  purification  effected  by 


264     DOMESTIC   SANITARY    ENGINEERING    AND   PLUMBING 

sand  filters,  organic  matter  being  oxidised  by  the  action 
of  nitrifying  organisms.  Efficient  nitration  largely  depends 
upon  the  rate  of  flow  through  the  filtering  medium,  and  upon 
the  condition  of  the  film  of  organic  matter  which  forms  on  the 
surface  of  the  sand. 

After  a  time  the  slimy  matter  clogs  up  the  surface  of  a 
filter,  and  its  filtering  capacity  requires  to  be  increased ;  this 
is  done  by  removing  a  thin  layer  of  sand,  which  should  be 
replaced  after  washing  unless  new  sand  is  substituted. 
When  a  sand  filter  has  been  cleansed,  or  when  it  is  new, 
water  should  be  allowed  to  stand  upon  it  for  about  30  hours, 
in  order  that  a  film  of  matter  may  be  deposited  upon  the 
sand  before  filtration  begins.  Where  very  pure  water  is 
required  the  first  flow  through  a  sand  filter  should  be  rejected, 
or  utilised  for  some  other  purpose. 

With  regard  to  the  depth  of  sand  for  a  small  rain-water 
filter,  this  should  be  about  1  foot,  and  deeper  where  practic- 
able. Each  square  foot  of  filter  surface  will  effectively  deal 
with  30  to  40  gallons  of  rain-water  per  day,  and  with  these 
low  rates  the  filter  afea  for  a  large  house  would  be  com- 
paratively small. 

Fig.  175  gives  a  plan  of  storage  tanks  and  filters,  together 
with  their  connections,  where  rain-water  is  supposed  to  be 
chiefly  utilised  as  the  supply  for  a  large  building.  Two 
hundred  gallons  of  filtered  water  are  required  per  day,  and  the 
storage  tank  T  has  a  water  capacity  of  16,000  gallons,  which 
represents  80  days'  supply.  A  rain-water  separator  E,  is 
provided  to  exclude  the  first  portion  of  the  rainfall  from  the 
storage  tank,  and  two  filters  are  arranged  to  work  independently 
of  each  other,  in  order  that  one  may  be  in  use  whilst  the  other 
is  cleansed.  The  filters  may  be  located  at  a  lower  level  than 
the  storage  tank,  and  the  supply  to  each  filter  may  be  con- 
trolled by  a  ball-cock  as  shown.  On  the  supply  pipes  to  the 
filters  three  stop-cocks  are  indicated,  which  are  numbered  1,2, 
and  3,  whilst  two  others  are  provided  on  the  outlets  of  the 
filters  and  numbered  4  and  5.  Stop-cocks  2  and  4,  3  and  5, 
serve  to  throw  the  filters  out  of  action,  whilst  stop-cock  No.  1 
is  intended  to  be  set  so  as  to  regulate  the  rate  of  flow  to  the 
filter.  Adjoining  the  filters  a  small  storage  tank  is  provided 


266     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

for  filtered  water,  which  may  hold  rather  more  than  one  day's 
supply. 

The  construction  of  the  filters  is  as  follows : — On  the  floors 
perforated  tiles  are  arranged,  which  allow  the  filtered  water 
to  flow  into  a  channel,  and  thence  to  the  small  storage  tank. 
About  six  inches  of  gravel  are  laid  upon  the  tiles,  and  upon 
the  gravel  1  foot  of  suitable  sand  is  placed.  To  prevent  the 
surface  of  the  sand  being  disturbed  by  inflowing  water,  the 
ball-cocks  may  deliver  into  small  earthenware  channels  which 
rest  upon  the  sand ;  in  this  way  the  water  would  be  better 
distributed  over  the  filter. 

A  sump  is  provided  at  the  outlet  end  of  the  large  storage 
tank  T,  and  here  a  sluice  may  be  arranged  in  order  that  the 
tank  may  be  emptied  when  desired.  An  overflow  to  the  tank 
is  provided,  and  is  shown  to  discharge  into  the  waste-water 
drain  from  the  separator.  The  tanks  and  filters  should  be 
properly  roofed  over  and  ventilated,  the  walls  and  floor 
rendered  water-tight,  and  ample  means  of  access  should  be 
provided.  Where  concrete  construction  is  adopted  it  can 
more  easily  be  rendered  water-tight  by  properly  grading  the 
aggregate.  A  good  concrete  mixture  for  water-tight  work  is 
1  part  cement,  2  parts  sand,  and  4  of  broken  stone,  the  latter 
being  broken  to  various  sizes. 

Where  only  a  comparatively  small  volume  of  rain  requires 
to  be  filtered,  household  filters  would  be  the  most  satisfactory 
to  use. 

Springs  as  a  Source  of  Water  Supply. — As  a  rule  springs 
yield  a  pure  and  wholesome  water,  on  account  of  the  latter 
having  percolated  long  distances  and  filtered  through  con- 
siderable mass  of  earth.  For  houses  in  rural  districts  springs 
form  good  sources  of  water  supply,  as  the  water  yielded  by 
them  is  usually  free  from  organic  impurity,  although  it  may 
contain  a  large  amount  of  carbonic  acid  gas  and  dissolved 
mineral  matter. 

There  are  two  kinds  of  springs :  (a)  surface  or  intermittent 
springs ;  (b)  permanent  or  deep-seated  springs. 

Surface  Springs. — A  surface  spring  may  occur  either  at  a 
low  point  on  the  side  of  a  hill,  or  at  the  side  of  a  valley,  where 
an  impervious  stratum  which  prevents  farther  downward 


WATER   SUPPLY  267 

progress  of  the  water  suddenly  appears  at  the  surface.  When 
rain  falls  upon  pervious  strata  at  a  high  level  it  gradually  flows 
downward  and  forward  in  its  underground  course,  until  it 
reappears  at  the  outcrop.  The  volume  of  water  yielded  by  a 
surface  spring  depends  upon  the  area  drained,  and  upon 
the  percentage  of  the  rainfall  which  percolates  into  the 
earth. 

As  their  name  implies,  the  volume  of  water  yielded  by  sur- 
face springs  is  readily  influenced  by  wet  and  dry  weather. 

Deep- Seated  Springs  differ  from  surface  springs  in  that 
the  water  is  forced  to  their  outlets  by  more  or  less  hydrostatic 
pressure,  whilst  the  water  of  surface  springs  simply  gravitates 
from  a  higher  to  a  lower  level,  and  is  under  no  hydrostatic 
pressure.  Deep-seated  springs  have  their  origin  where  the  rain, 
after  percolating  through  porous  strata  at  a  high  elevation, 
eventually  becomes  confined  between  impervious  strata  and 
sinks  to  a  lower  level  than  its  point  of  escape.  The  water 
of  these  springs  usually  travels  long  distances  through  porous 
rocks,  and  when  it  has  reached  its  lowest  point  the  water 
there  accumulates  until  sufficient  pressure  is  produced  to  force 
it  through  some  fissure  in  the  strata.  Owing  to  these  large 
subterranean  accumulations  of  water,  deep-seated  springs  yield 
a  more  nearly  permanent  rate  of  flow. 

Spring  water  is  clear  and  sparkling,  owing  to  its  having 
filtered  long  distances  through  porous  strata,  and  with  having 
absorbed  large  volumes  of  carbonic  acid  gas  in  its  passage. 
Where  spring  water  is  used  for  supplying  one  or  more  buildings 
in  a  rural  district,  a  spring  may  frequently  be  chosen  which  is 
sufficiently  high  to  give  a  gravitation  supply  by  providing  a 
suitable  storage  tank  which  either  adjoins  or  is  located  some 
distance  from  it. 

With  regard  to  the  size  of  storage  tanks,  in  this  case  it 
will  depend  upon  the  volume  of  water  yielded  by  the  spring, 
whether  the  yield  is  fairly  uniform  or  not,  upon  the  volume 
of  water  required,  and  whether  water  is  stored  for  extinguish- 
ing fires. 

If  the  yield  of  a  spring  is  greater  than  the  demand, 
only  a  small  storage  tank  may  be  essential ;  but  if  the  demand 
for  water  at  certain  times  greatly  exceeds  the  rate  of  supply, 


268     DOMESTIC    SANITARY    ENGINEERING    AND   PLUMBING 

then  a  larger  reserve  will  be  required.  Under  the  latter 
circumstances  the  capacity  of  a  tank  may  be  equal  to  anything 
from  about  4  days'  to  4  weeks'  supply,  according  to  the  require- 
ments to  be  satisfied. 

The  storage  capacity  for  fire  extinction  cannot  be  definitely 
fixed  for  small  supplies,  as  so  much  depends  upon  the  special 
circumstances  of  each  particular  case. 

Owing  to  the  freedom  of  spring  water  from  organic  pollution, 
no  further  filtering  of  this  water  is  usually  required.  The 
outlet  pipe  from  a  storage  tank  should  be  protected  by  either 
a  copper  rose  or  a  wire  screen,  in  order  to  prevent  any  foreign 
matter  which  may  enter  a  tank  from  being  drawn  into  the 
pipe. 

A  suitable  overflow  should  be  provided,  and  where  a  storage 
tank  is  large  provision  should  be  made  for  emptying  it.  If  a 
spring  be  large,  the  supply  to  a  storage  tank  may  be  regulated 
by  a  ball-cock,  whilst  in  the  case  of  a  more  limited  supply  the 
whole  of  the  water  may  flow  to  the  tank. 

When  springs  occur  at  lower  levels  than  the  buildings  to 
be  supplied,  great  care  is  necessary  to  guard  against  possible 
pollution  of  the  water.  The  usual  appliances  for  raising 
water  to  higher  levels  are  pumps  and  hydraulic  rams,  the  latter 
being  specially  suitable  where  there  is  sufficient  water  to  work 
them. 

A  simple  method  of  finding  the  volume  of  water  a  spring 
will  yield  is  that  of  first  ascertaining  by  means  of  a  stop- 
watch how  long  it  takes  to  fill  one  or  more  buckets  of  known 
capacity. 

A  convenient  place  can  usually  be  found  where  a  stream 
from  a  spring  may  be  impounded,  and  by  means  of  a  spout  or 
channel  after  the  water-level  has  adjusted  itself,  the  yield  may 
be  readily  gauged,  and  expressed  in  gallons  per  minute  or  in 
any  other  units  desired.  Thus,  if  a  bucket  has  a  capacity  of 

2 J  gallons  and  is  filled  in  25  seconds,  the  yield  =  2ix6°  =  5  x  ~ 

ZiD  2i       ^!iD 

—  6  gallons  per  minute,  or  6  x  60  =  360  gallons  per  hour. 

Wells  as  a  Source  of  Supply. — In  country  districts  under- 
ground water  often  forms  the  principal  source  of  supply,  and 
where  it  does  not  issue  in  the  form  of  a  spring  it  is  often 


WATER   SUPPLY 


269 


necessary  to  tap  it  by  means  of  a  well.  The  quality  of  well 
waters  is  very  similar  to  those  from  springs,  and  depends  upon 
the  nature  of  the  strata  through  which  they  have  passed. 
Well  water,  however,  is  very  liable  to  pollution  unless  the 
wells  are  suitably  located,  properly  constructed,  and  protected 
by  covering  them. 

There  are  three  classes  of  wells — 

(a)  Surface  wells. 

(b)  Deep  wells. 

(c)  Artesian  wells. 

Driven  tube  wells  may  be  classified  as  either  surface  or 
deep  wells,  according  to  the  geological  formation  through 
which  they  are  driven. 

Surface  Wells  are  those  which  are  sunk  in  the  subsoil, 


A 


FIG.  176.— Subsoil  well. 

the  water  being  held  up  by  an  impervious  stratum  as  in 
Fig.  176.  Kain  after  falling  upon  the  permeable  formation 
percolates  downward  until  its  progress  is  arrested,  and  the 
whole  of  the  porous  strata  below  the  line  AB  is  saturated 
unless  water  is  withdrawn  by  pumping;  any  further  water 
which  percolates  from  the  upper  surface  escapes  at  B  in  the 
form  of  a  spring. 

The  chief  objection  to  surface  wells  are,  their  waters  are 
often  exposed  to  sewage  pollution,  owing  to  leaky  drains  and 
cesspools,  and  by  surface  impurities  being  washed  by  rain 
into  the  subsoil;  the  waters  yielded  by  surface  wells  are 
usually  very  hard,  and  not  very  suitable  for  general  household 
use.  So  far,  however,  as  the  danger  to  pollution  is  concerned, 
this  may  be  reduced  to  a  minimum  by  making  these  wells  in 
non-polluted  areas,  and  by  constructing  the  upper  12  feet  of 


270     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


MONKEY 


their  depth  with  water-tight  linings,  which  are  continued 
9  inches  or  so  above  the  level  of  the  ground. 

Driven  Tube  Wells. — In  soft  soils  a  cheap  supply  of  water 
may   frequently   be   obtained   by   an   Abyssinian   tube   well. 
These  wells  are  formed  by  driving  strong  iron  tubes  to  near 
the  water-bearing  stratum.     The  usual  sizes  of  the  tubes  are 
from  1J  to  3  inches  diameter,  the  difficulty  of  driving  increas- 
ing as    the   sizes    of   the   tubes   are 
increased.     To   facilitate   driving  the 
tubes   should    not   exceed   6   feet  in 
length,  and  shorter  ones  in  some  cases 
may  be  desirable. 

The  method  of  driving  the  tubes 
is  chiefly  governed  by  their  size  and 
the  nature  of  the  earth  to  be  pierced. 
For  driving  the  smallest  sizes  a  sledge 
hammer  may  suffice,  or  the  method 
shown  in  Fig.  177  may  be  adopted, 
where  a  weight  or  monkey  falls  on  to 
a  driving  cap  which  is  attached  to  the 
top  of  the  tube.  Where  a  heavy 
monkey  is  used  it  is  raised  by  means 
of  ropes  and  pulleys. 

The  first  and  perforated  tube  is  3 
feet  long,  and  is  provided  with  a 
driving  point,  which  is  a  little  larger 
at  A  than  the  tube  itself,  in  order 
that  a  hole  may  be  made  sufficiently 
large  to  just  clear  the  sockets.  In 
size  the  perforations  are  about  J  inch 
diameter,  but  when  the  tubes  are 

driven  into  fine  sand,  the  holes  may  be  reduced  in  size 
by  covering  them  with  brass  strainers.  It  is  necessary 
when  first  starting  to  drive  the  tubes  to  see  that  they 
are  exactly  vertical,  otherwise  the  well  may  result  in 
failure. 

As  each  length  of  tube  is  driven  in  the  ground  another 
is  added,  and  this  process  continues  until  the  desired  depth 
has  been  reached,  when  a  pump  is  attached  to  the  top  of  the 


FIG.  177.— Method  of  driv- 
ing tubes  for  an  Abyssin- 
ian tube  well. 


WATER    SUPPLY 


271 


tubes.  When,  however,  a  well  of  the  driven  type  is  used  its 
depth  will  be  limited  to  about  30  feet- 
Tubes  can  only  be  driven,  of  course,  through  soft  loose 
strata,  such  as  sand,  fine  gravel,  etc.,  as  in  Fig.  178.  Where 
firm  strata  is  to  be  penetrated  the  hole  for  the  tubes  requires 
to  be  bored.  After  the  tubes  have  been  driven  to  the  required 
depth,  Fig.  178,  a  cavity  requires  to  be  made  in  which  water 
may  accumulate,  or  pumping 
would  be  difficult  if  water 
were  drawn  directly  from  the 
surrounding  earth.  The  cavity 
may  be  formed  by  allowing 
the  column  of  water  in  the 
tubes  which  form  the  suction 
pipe  to  fall  back  a  number 
of  times  by  destroying  the 
vacuum,  and  so  loosen  the 
sand  which  surrounds  the 
perforated  tube.  To  aid  in 
removing  sandy  matter  which 
enters  the  tube  it  is  better  to 
use  a  common  galvanised  iron 
pump,  as  grit  has  a  destruc- 
tive effect  upon  the  working 
parts  of  a  pump.  The  vacuum 
in  the  suction  pipe  may  be 
broken  during  the  formation 
of  a  cavity  by  providing  a 
short  length  of  tube  with  a 
tee,and  by  temporarily  joining 

it  at  P,  Fig.  178.  A  pump  may  then  be  screwed  into  the  upper 
opening  of  the  tee,  whilst  a  stop-cock  may  be  fixed  to  the 
remaining  connection.  After  the  pump  has  been  primed  and 
a  few  strokes  made,  the  water  rises  to  the  outlet,  when,  upon 
quickly  opening  the  cock,  air  is  admitted  and  the  water  falls 
to  loosen  the  earth  surrounding  the  perforated  tube.  This 
operation  can  be  repeated  until  the  cavity  is  sufficiently  large, 
and  the  temporary  pump  may  be  removed  and  the  permanent 
one  installed. 


FIG.  178. — Abyssinian  tube  well. 


272     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


Deep  Wells  differ  from  surface  wells  inasmuch  as  the 
latter  only  tap  the  subsoil  water,  whilst  deep  wells  tap  water 
which  is  located  beneath  the  impervious  stratum  which  sup- 


5UBSOIL 

WELL. 


\  %  ^  IVH'  'i  -' 'V1'   <•<'>•  •.,:•'••••  vVi !  i 


FIG.  179.  —  Formation  showing  subsoil  and  deep  wells. 

ports  the  subsoil  water.  The  actual  depth  of  a  well  does  not 
decide  the  class  to  which  it  belongs,  and  a  so-called  surface 
or  subsoil  well  in  one  locality  might  be  much  deeper  than  a 
so-called  deep  well  in  another  district.  Fig.  179  clearly  shows 
the  difference  between  surface  or  subsoil  and  deep  wells. 


<C  FAULT 


FIG.  180. — Formation  showing  fault. 

Deep  well  water  is  usually  very  pure  on  account  of  its 
having  filtered  long  distances,  and  by  the  protection  afforded 
it  by  the  overlying,  impervious  stratum.  It  is  essential, 


WATER   SUPPLY 


273 


however,  where  deep  wells  are  constructed,  to  have  the  whole 
of  their  linings  watertight  in  the  subsoil  and  to  exclude 
surface  impurity. 

The  amount  of  water  yielded  by  a  deep  well  depends  upon 
the  area  of  the  outcrop,  and  upon  the  volume  of  rain  which 
enters  it,  upon  the  dip  of  the  strata,  upon  the  depth  of  the 
well,  and  whether  the  geological  formation 
is  free  from  faults. 

Fig.  180  shows  the  effect  a  fault  may 
have.  The  impervious  stratum  on  the  right 
side  of  the  fault  imprisons  water  in  the 
porous  strata  on  the  left  side,  owing  to  the 
dip  of  the  underlying  impervious  stratum 
being  in  the  direction  shown.  A  well  sunk 
at  C  would  thus  yield  water,  whilst  one 
at  D  would  result  in  failure  owing  to  the 
underground  flow  being  cut  off  by  the  fault. 
Even  if  it  is  assumed  that  a  little  water 
may  be  found  at  D,  it  would  readily  be 
drained  by  a  well  which  was  sunk  at  a 
lower  point  to  the  right  of  the  fault. 

Bore-Holes. — When  it  is  necessary  to 
penetrate  the  earth  to  great  depths  through 
hard  strata  in  order  to  obtain  water,  bore- 
holes, Fig.  181,  are  often  resorted  to.  In 
their  upper  and  enlarged  part  the  air- 
vessels  and  connecting  rods  are  arranged. 
Bore-holes  vary  from  4  inches  diameter  to 
over  36  inches  diameter,  and  their  depth 
may  range  from  40  to  over  2000  feet. 

Artesian  Wells. — The  water  in  artesian 
wells  is  under  hydrostatic  pressure,  and 
owing  to  the  impervious  strata  being  pierced  under  which 
the  water  is  confined,  the  latter  rises  to  the  surface  and 
overflows  at  the  mouth  of  the  well.  Fig.  182  shows  a 
formation  which  produces  an  artesian  well ;  the  strata  on 
each  side  outcrop  at  a  high  level,  where  the  rain-water  enters 
and  percolates  downwards  to  the  lower  level ;  here  the  water 
accumulates  under  pressure  on  account  of  the  plane  of  satura- 
18 


FIG. 


181.—  Bore-hole 
well. 


274     DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 

tion  occurring  at  a  high  level.  If  a  bore-hole  W,  Fig.  182, 
is  driven  until  it  penetrates  the  lower  permeable  strata,  water 
immediately  rises  and  overflows  the  top  of  the  bore-hole.  In 
other  cases  water  may  be  unable  to  rise  to  the  top  of  the 
well,  but  it  may  rise  in  the  bore-hole  to  a  considerable  height, 
and  by  so  doing  reduce  the  cost  of  pumping. 

Upland  Surface  Water  is  frequently  obtained  from  un- 
cultivated mountain  regions,  which  are  well  removed  from 
the  abode  of  man.  This  water  is  usually  soft  and  free  from 
animal  pollution,  but  in  times  of  storm  it  is  often  discoloured, 
and  if  it  flows  over  peaty  surfaces  acidity  is  imparted  to  the 
water,  and  this  frequently  causes  it  to  attack  lead  pipes. 

River  Water  as  a  rule  does  not  prove  an  ideal  supply, 
but  in  some  cases  it  is  the  only  water  that  is  available  in 


FIG.  182. — Formation  producing  an  artesian  well. 

sufficient  volume  and  at  a  reasonable  cost.  To  render  river 
water  fit  for  drinking  purposes  it  should  be  obtained  from  a 
point  well  above  the  line  of  pollution,  and  be  subjected  to 
sand  filtration.  As  river  and  upland  surface  waters  are  only 
utilised  by  large  communities,  a  lengthy  treatment  of  these 
is  beyond  the  scope  of  this  work. 

Hardness    of   Water.  —  The    following    is    the    order    of 
different  waters  with  regard  to  their  softness : — 

1.  Kain  water. 

2.  Upland  surface  water. 

3.  River  water. 

4.  Spring  water. 

5.  Deep  well  water. 

6.  Shallow  well  water. 

Although  we  speak  of  water  as  being  "hard"  or  "soft," 


WATER   SUPPLY  275 

these  terras  are  only  relative,  as  most  soft  waters  contain 
a  certain  amount  of  hardness.  Hardness  in  water  is  measured 
in  degrees,  a  degree  of  hardness  being  equal,  according  to 
Dr.  Clarke's  scale,  to  1  grain  of  bicarbonate  of  lime  in  1  gallon 
of  water.  The  amount  of  hardness  in  water  is  frequently 
determined  by  standard  soap  solution. 

Hard  water  is  readily  known  by  the  manner  in  which  it 
curdles  soap,  and  by  its  characteristic  roughness  to  the  skin. 
Soft  water,  on  the  other  hand,  feels  smooth  to  the  touch,  and 
forms  a  free  lather  with  soap. 

In  general,  soft  water  is  understood  to  be  water  which 
contains  not  more  than  5  degrees  of  hardness,  and  hard  water 
that  which  contains  more  than  5  degrees. 

As  rain  is  the  primary  source  of  all  our  water  supplies, 
all  waters  are  at  the  outset  soft,  and  hardness  is  produced  by 
their  dissolving  traces  of  mineral  matter  when  either  per- 
colating through  the  earth  or  when  flowing  over  the  earth's 
surface.  Hardness  is  of  two  kinds,  one  being  termed  "  tem- 
porary "  and  the  other  "  permanent." 

Temporary  hardness  is  principally  due  to  lime  salts  when 
in  the  form  of  bicarbonate  of  lime,  the  bicarbonate  being 
held  in  solution  by  carbonic  acid  gas.  In  the  absence  of  this 
gas  water  will  only  dissolve  traces  of  carbonate  of  lime. 

Permanent  hardness  is  chiefly  caused  by  the  water  dis- 
solving sulphate  of  lime,  which  may  take  the  form  of  spar  or 
gypsum.  It  differs  from  temporary  hardness  inasmuch  as 
sulphates  are  dissolved  in  either  the  presence  or  absence  of 
carbonic  acid  gas,  the  latter  not  being  in  any  way  responsible 
for  sulphates  passing  into  solution. 

A  water  moderately  hard  is  advantageous  for  dietetic 
purposes,  but  for  laundry  uses  a  certain  amount  of  soap  must 
be  decomposed  to  remove  the  hardness  before  a  lather  can 
be  formed.  Hard  waters  also  give  trouble  in  boilers,  and 
in  their  connections,  by  causing  earthy  matters  which,  produce 
the  hardness  to  be  precipitated  and  to  form  a  scale  on  the 
surfaces  of  pipes  and  boilers.  In  the  case  of  a  hot-water 
heater  which  is  supplied  with  temporary  hard  water,  the 
latter  upon  having  its  temperature  raised  to  about  200°  F. 
causes  the  carbonates  to  be  deposited.  If,  on  the  other  hand, 


276     DOMESTIC   SANITARY   ENGINEERING   AND   PLUMBING 

the  same  heater  was  supplied  with  water  containing  per- 
manent hardness,  the  raising  of  the  water  to  200°  F.  would 
have  practically  no  effect  upon  the  hardness.  Should, 
however,  the  temperature  of  the  water  be  raised  to  300°  F. 
and  over,  some  of  the  sulphates  may  also  be  precipitated. 

A  steam  boiler  differs  from  a  hot- water  heater,  for  in  the 
former  the  water  is  evaporated,  and  in  consequence  turns  out 
both  forms  of  hardness. 

Softening  Water. — On  account  of  the  general  advantages 
derived  by  the  use  of  soft  water,  the  softening  of  hard  water 
is  often  resorted  to.  Certain  industries,  for  example,  can 
only  be  carried  on  with  soft  water,  but  these  when  conducted 
on  a  large  scale  are  usually  located  in  districts  that  have  a 
suitable  water  supply.  The  methods  adopted  for  softening 
water  are  by  boiling  it  in  a  suitable  apparatus,  and  by 
chemically  treating  it.  The  first  method  is  limited  to 
softening  temporary  hard  water,  whilst  the  other  may  be 
adopted  for  reducing  either  temporary  or  permanent  hardness. 

The  more  simple  method  of  softening  water  is  by  boiling  it, 
as  only  a  single  operation  is  involved.  While,  however,  this 
method  is  very  suitable  for  both  sterilising  and  softening  small 
volumes  of  temporary  hard  water,  it  would  prove  a  very 
expensive  operation  when  dealing  with  large  volumes  for 
industrial  purposes ;  in  many  cases  softening  by  boiling  would 
be  impracticable. 

Softening  by  suitable  chemical  reagents  is  the  general 
method  adopted,  when  either  treating  the  whole  of  the  supply 
for  a  district  or  a  limited  volume  of  water  for  industrial  uses. 
For  a  chemical  process  to  be  successful,  the  reagents  must  be 
added  in  the  correct  proportions,  and  be  thoroughly  mixed 
with  the  water  to  be  treated ;  provision  is  also  necessary  to 
prevent  carbonates  settling  out  of  the  treated  water  and 
causing  deposits  in  pipes  and  in  their  connections. 

When  lime  in  the  form  of  lime-water  is  used  as  the  reagent 
for  removing  temporary  hardness,  the  lime  absorbs  the  carbonic 
acid  gas,  for  which  it  has  a  great  affinity,  and  the  carbonates 
are  precipitated  chiefly  in  the  form  of  carbonate  of  lime. 

As  many  waters  contain  both  temporary  and  permanent 
hardness,  the  removal  of  the  latter  is  accomplished  by  adding 


WATER   SUPPLY  277 

other  reagents  which  decompose  the  earthy  matter  producing 
the  hardness. 

A  method  of  softening  water  by  The  Pulsometer  Engin- 
eering Company  is  given  in  Fig.  183.  At  the  highest  point 
a  tank  is  provided,  which  is  divided  to  form  a  large  and  a 
small  compartment ;  the  larger  one  regulates  the  volume  of 
water  to  be  treated  at  one  time,  and  is  provided  with  a  siphon 
to  automatically  effect  its  discharge  when  full  of  water.  Prior 
to  the  water  being  discharged  it  overflows  the  division,  and 
fills  the  smaller  compartment ;  the  outlet  valve  in  the  latter 
is  controlled  by  the  lever  shown,  which  in  turn  is  operated  by 
the  rising  and  sinking  of  the  float.  To  the  outlet  of  the 
smaller  compartment  of  the  upper  tank  a  pipe  is  joined,  the 
other  end  of  the  pipe  being  connected  to  the  bottom  of  the 
smaller  cylindrical  tank,  which  contains  lime-water.  Another 
small  tank  contains  a  solution  of  soda,  or  other  suitable  reagent, 
which  is  used  in  measured  doses  by  means  of  the  bucket  which 
is  connected  with  the  lever.  The  bucket  is  filled  with  the 
soda  solution  upon  being  submerged  by  the  rising  of  the  float 
in  the  large  compartment.  To  effect  the  discharge  of  the 
solution  from  the  bucket  a  small  Wertenburg  siphon  is 
employed,  the  outlet  end  of  which  delivers  into  the  mixer. 
The  outlet  from  the  large  tank  and  that  from  the  lime-water 
tank  also  discharge  into  the  mixing  chamber,  which  is  located 
at  the  top  of  the  large  settling  tank.  From  the  mixing  chamber 
a  pipe  is  taken,  and  its  lower  end  terminates  near  the  bottom 
of  the  settling  tank  ;  from  the  latter  an  outlet  pipe  is  joined  to 
the  upper  part  of  a  filter,  which  is  placed  beneath  the  lime- 
water  tank. 

The  working  of  the  softening  plant  is  as  follows  : — As  the 
water  to  be  treated  fills  the  upper  tank,  the  float  at  the  same 
time  rises  and  operates  the  lever  to  lower  and  submerge  the 
bucket  in  the  soda  tank ;  as  the  water  continues  to  rise  in  the 
float  compartment  it  eventually  overflows  to  fill  the  adjoin- 
ing compartment  until  a  given  point  is  reached,  when  the 
siphon  is  brought  into  action  and  the  contents  of  the  tank  are 
discharged.  Simultaneously  with  the  discharge  of  the  water 
from  the  large  tank  the  valve  in  the  smaller  compartment  is 
opened,  when  its  contained  water  displaces  an  equivalent 


HARD  WATER 
0 
IfcCT 


SODA  SVPHQN 


FIG.  183. — The  Criton  water  softener  (Pulsometer  Engineering  Co.). 


WATER    SUPPLY  279 

volume  of  lime-water  from  the  cylindrical  tank  beneath.  The 
bucket  which  has  received  its  charge  of  soda  solution  is 
gradually  raised  by  the  falling  float,  and  the  discharge  of  the 
solution  begins  by  the  small  siphon  coming  into  action.  By 
the  simultaneous  discharge  of  water  and  the  chemical  re- 
agents into  the  mixing  trough  the  whole  are  mixed  together 
and  flow  to  the  bottom  of  the  settling  tank.  In  the  latter 
tank  the  greater  percentage  of  the  salts  settle  out  of  the 
water,  and  they  are  precipitated  in  the  form  of  mud.  From 
the  settling  tank  the  treated  water  flows  to  the  filter,  and  any 
carbonates,  etc.,  which  remain  in  suspension  are  intercepted  on 
the  surface  of  the  filtering  medium.  At  the  bottom  of  the 
settling  tank  a  stop-cock  is  provided  which  admits  of  excess  of 
sludge  being  withdrawn.  The  periodical  cleansing  of  the  filter 
is  accomplished  by  admitting  water  under  pressure  through 
the  valve  at  the  bottom  of  the  filter,  when  its  upward  passage 
displaces  the  deposited  matter  from  the  filtering  medium,  and 
both  escape  at  the  washout  provided  at  the  top  of  the  filter. 

To  produce  the  lime-water,  slaked  lime  is  first  placed 
in  the  lime-water  tank,  and  during  the  upward  passage 
of  the  water  the  latter  becomes  saturated  with  lime.  Fresh 
lime  is  added  daily  or  as  required,  the  old  or  spent  lime 
being  discharged  by  opening  the  wash-out  valve. 

The  soda  solution  is  of  known  strength,  and  is  added  when 
it  is  found  necessary. 

The  Archbutt-Deeley  Process  of  softening  water  is  one  that 
has  been  largely  adopted.  In  this  system  square  or  rectangular 
tanks  are  used,  their  depths  varying  from  7  to  10  feet.  The 
chemicals  used  are  similar  to  those  employed  in  the  system 
already  described,  but  the  two  installations  differ  considerably 
in  design  and  in  the  mode  of  operation.  In  the  "  Criton " 
softener,  Fig.  183,  the  chemicals  are  added  automatically,  whilst 
in  the  Archbutt-Deeley  process  no  attempt  is  made  to  render 
the  installation  automatic  in  action,  and  the  chemicals  are 
added  by  an  attendant. 

In  the  latter  system,  after  a  tank  has  been  filled  to  the 
desired  height  with  hard  water,  the  chemical  reagents  are 
caused  to  be  diffused  throughout  the  whole  body  of  the  water 
by  the  aid  of  perforated  horizontal  pipes,  in  conjunction  with  a 


280     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

circulating  arrangement  which  is  operated  with  "  live  "  steam. 
To  accelerate  subsidence  in  the  treated  water  some  of  the 
previous  precipitated  matter  is  caused  to  be  stirred  by  blowing 
air  through  perforated  pipes,  which  are  fixed  near  the  bottom 
of  the  tank,  and  the  water  is  afterwards  allowed  to  remain 
quiescent  for  about  an  hour  or  so  whilst  precipitation  takes 
place.  The  softened  water  is  then  withdrawn  from  the 
surface  of  the  tank  by  means  of  a  hinged  floating  arm  in 
connection  with  the  outlet  valve. 

To  prevent  carbonates  settling  out  of  the  softened  water 
the  latter  is  carbonated.  Carbonating  is  effected  with  carbonic 
acid  gas,  which  is  produced  by  a  coke  stove,  by  causing  the 
gas  to  come  in  contact  with  the  water  as  the  latter  flows  from 
the  softening  tank. 

There  are  many  other  types  of  water  softening  apparatus 
in  use,  but  for  any  type  using  chemical  reagents  to  be 
satisfactory  the  chemicals  require  to  be  added  in  correct 
proportions  and  strengths,  and  to  be  thoroughly  mixed  with 
the  water  to  be  treated. 

Constant,  Partially  Constant,  and  Intermittent  Supplies. — 
The  value  of  a  constant  water  supply  is  generally  recognised ; 
the  water  being  always  on  under  pressure  in  the  street  mains 
— excepting  when  repairs  or  alterations  are  being  effected — 
can  be  withdrawn  in  a  fresh  condition,  whilst  storage  cisterns 
are  not  essential,  and  the  possibility  of  pollution  is  much  less 
than  with  any  other  form  of  supply. 

An  intermittent  supply  may  be  due  to — 

(a)  Insufficiency  of  water  to  maintain  a  constant  supply ; 

(b)  Draw-off  taps  being  located  in  elevated  positions  relative 

to  the  source  of  supply ; 

(c)  The  mains   being   too   small  to   supply   higher  levels 

when    there  is  more  or   less   considerable  draught 
upon  them  at  lower  points. 

Under  the  latter  conditions  the  supply  may  be  termed 
a  "  partially  constant "  one,  as  the  failure  of  the  supply  may 
only  occur  with  an  abnormal  draught  during  certain  periods 
of  a  day. 

Very  often  the  term  "  intermittent "  is  confined  to  supplies 
where  the  water  is  only  turned  on  to  the  consumers  for  q, 


WATER    SUPPLY  281 

number  of  hours  each  day,  although  such  measures  may  only 
be  necessary  at  certain  times  each  year  when  the  supply  is 
running  short.  In  partially  intermittent  supplies  there  may 
be  no  lack  of  water  at  the  source,  but  the  distributing  mains 
may  be  inadequate  at  certain  periods  to  meet  the  demand 
upon  them. 

Arrangement  of  Service  Pipes. — The  kind  of  supply 
naturally  regulates  to  a  great  extent  the  general  arrangements 
of  service  pipes.  For  example,  where  a  water  supply  to  a 
building  is  on  the  constant  system,  all  draw-off  taps  from 
which  drinking  water  is  drawn  should  be  supplied  directly 
from  the  street  mains.  Where  there  is  considerable  pressure 
of  water  it  is  often  desirable  to  supply  the  cold  draw-off  taps 
to  baths  and  similar  fittings,  especially  in  large  buildings,  from 
an  overhead  storage  cistern,  to  avoid  undue  wear  and  tear  upon 
the  water  fittings. 

In  the  case  of  an  intermittent  supply  it  is  necessary  to 
serve  the  whole  of  the  fittings  from  storage  tanks,  and  the 
service  pipes  require  to  be  large  enough  to  fill  the  cisterns 
during  the  period  the  water  is  turned  on.  Should  a  supply 
be  a  partially  constant  one,  some  of  the  draw-off  taps  will 
necessarily  require  to  be  supplied  from  a  storage  tank, 
whilst  others  may  be  directly  connected  with  the  house 
service  pipe. 

In  high  buildings  it  becomes  necessary  under  certain 
conditions  to  supply  the  taps  on  the  upper  floors  from  cisterns, 
whilst  those  at  lower  levels  may  have  a  constant  or  direct 
supply.  For  dwellings  where  a  constant  supply  cannot 
entirely  be  relied  upon,  a  direct  supply  from  a  street  main 
and  a  supply  from  a  storage  cistern  can  with  advantage  be 
laid  on  to  each  kitchen  or  scullery  sink. 

The  drawbacks  of  cistern  supplies  are :  the  water  loses  its 
freshness,  and  is  liable  to  pollution  by  foreign  matter  gaining 
access  to  cistrens  unless  precautionary  measures  are  adopted. 

With  regard  to  the  sizes  of  service  pipes,  those  of  j  inch 
diameter  may  be  considered  the  minimum  for  ordinary  dwell- 
ings which  have  a  constant  supply,  whilst  a  larger  size  is 
essential  where  the  supply  is  an  intermittent  one. 

Water  companies,  to  whose  system  service  pipes  are  to  be 


282     DOMESTIC   SANITARY    ENGINEERING   AND   PLUMBING 

joined,  often  stipulate  the  sizes  of  the  pipes  necessary  for 
different  buildings,  but  the  sizes  of  service  pipes  may  be 
calculated  for  special  cases,  provided  the  necessary  data  are 
available. 

In  large  buildings  where  provision  is  made  for  extinguish- 
ing fires,  or  where  large  volumes  of  water  are  necessary  for 
trade  purposes,  the  supply  pipes  may  require  to  be  from  3  to 
6  inches  diameter. 

As  far  as  possible  water  pipes  should  be  placed  beyond  the 
reach  of  frost  by  fixing  them  on  the  inside  walls  of  buildings, 
and  by  laying  them  in  the  ground  to  a  minimum  depth  of  2  ft. 
6  in.  When  it  is  imperative  to  fix  water  pipes  in  exposed 
situations  they  should  be  well  protected  by  a  thick  covering 
of  hair  felt  or  other  suitable  insulating  material. 

In  many  buildings  pipes  can  be  arranged  that  they  may 
be  emptied  of  water  by  making  them  fall  to  given  points, 
where  draw-off  taps  should  be  provided.  In  order  to  empty 
water  pipes  air  requires  to  be  admitted  at  the  higher  points, 
after  the  stop-cocks  are  closed.  This  method  of  preventing 
damage  to  water  pipes  by  frost  can  advantageously  be  adopted 
for  sections  of  buildings  which  are  not  used  during  the  winter 
months. 

A  Stop-Cock  should  be  fixed  on  a  service  pipe  at  a  point 
near  to  the  boundary  of  a  building,  and  an  additional  stop- 
cock should  be  fixed  to  each  service  inside  a  building,  to 
enable  the  water  to  be  turned  off  when  it  is  desired. 

In  small  houses  which  are  arranged  in  terrace  form,  and 
for  tenement  buildings,  one  service  pipe  is  often  common  to 
a  number  of  dwellings,  and  under  these  circumstances  the 
branch  services  should  be  separately  controlled  by  stop-cocks. 

For  large  buildings,  where  the  control  of  the  water  supply 
in  any  section  is  of  importance,  every  important  branch  should 
be  provided  with  a  stop-cock. 

Underground  Stop-Cocks  should  be  made  as  accessible  as 
possible.  A  good  method  is  that  of  fixing  a  permanent 
wrought-iron  key  to  the  crutch  of  the  stop- cock,  and  the  key 
should  reach  nearly  to  the  top  of  the  stop-cock  eye,  which 
finishes  flush  with  the  road  surface  as  in  Fig.  184.  An  eye  is 
usually  built  with  bricks,  but  in  many  cases  it  may  be  formed 


WATER   SUPPLY 


283 


with  a  6-inch  or  a  9-inch  drain  pipe,  which  rests  upon  a  firm 
foundation.  Permanent  keys  may  not  be  desirable  for  all 
situations,  and  where  a  stop-cock  is  likely  to  be  interfered 
with  a  loose  key  should  be  provided. 

Both  plug  and  screw-down  types  of  stop-cocks  are  used 
for  service  pipes,  but  the  latter  is  the  more  generally  used. 
Each  class  of  cock,  however,  has  its  merits  and  drawbacks. 
The  points  in  favour  of  screw-down  taps  are  they  can  only  be 
slowly  closed,  concussion  is  avoided,  they  are  more  easily 
repaired,  and  they  are  cheaper  than  plug  taps. 

The  principal  drawbacks 
of  screw-down  taps  for  under- 
ground situations  are  their 
relative  weakness,  liability  of 
leakage  at  the  stuffing  boxes, 
and  unless  discretion  is  exer- 
cised in  closing  them  with 
keys  which  have  a  large 
leverage  the  top  of  the 
taps  is  liable  to  be  broken. 
The  omission  of  a  set  screw 
in  a  screw  -  down  tap  has 
occasionally  resulted  in  the 
top  being  screwed  off  when 
inadvertently  opening  it. 

With  regard  to  the  merits 
of  plug  taps  when  located 

underground,  they  are  stronger  and  less  liable  to  leakage  than 
screw-down  taps. 

The  principal  drawback  of  plug  taps  is  the  excessive  strain 
to  which  the  pipes  are  subjected  when  the  taps  are  quickly 
closed.  This  drawback,  however,  does  not  always  exist, 
and  in  the  case  of  underground  taps  they  get  stiff  to  turn 
through  infrequent  use,  and  therefore  do  not  admit  of  being 
quickly  closed. 

Connections  of  Service  Pipes  with  Street  Mains. — Service 
pipes  are  joined  with  tapping  mains  when  either  the  water 
is  on  under  pressure  or  when  the  mains  are  emptied  of  water. 
The  appliance  used  (Fig.  185)  for  joining  service  pipes  with 


FIG.  184. — Stop-tap  eye  and  cover. 


284     DOMESTIC    SANITARY    ENGINEERING   AND    PLUMBING 
a   main  when  the  water  is  on   under  pressure  contains  two 


FIG.  185. — Apparatus  for  drilling  and  tapping  water  mains  when 
under  pressure  (Palatine  Engineering  Co..  Liverpool). 

principal  parts :  one  part  holds  a  combination  drill  and  screwing 
tap,  for  cutting  and  preparing  the  hole  in  the  iron  main  at  one 


WATER   SUPPLY  285 

operation ;  whilst  the  other  part  holds  a  stop-cock  ferrule  L, 
which  is  screwed  into  the  prepared  hole  after  moving  the  fer- 
rule to  the  position  previously  occupied  by  the  drill.  The 
appliance  when  properly  fixed  on  the  main  to  be  tapped  forms 
a  water-tight  joint,  and,  owing  to  the  movable  spindles  D  and 
E  working  through  stuffing  boxes,  little  water  escapes  during 
the  drilling  and  tapping  of  the  mains. 

Storage  Cisterns  which  are  fixed  in  the  higher  parts  of 
buildings  may  be  formed  of  earthenware,  slate,  wrought  and 
cast  iron,  mild  steel,  and  of  woodwork  which  is  lined  with 
suitable  sheet  metals. 

Glazed  earthenware,  or  porcelain,  cisterns  possess  the 
advantage  of  easy  cleansing,  and  they  are  also  free  from 
corrosion.  Their  weight  is  their  chief  drawback. 

Slate  Cisterns,  like  those  of  porcelain,  are  free  from  the 
corrosive  action  of  certain  waters,  and  if  properly  jointed 
are  suitable  for  storing  drinking  water.  As  slate  cisterns  are 
formed  of  slabs  which  are  grooved  and  bolted  together,  they 
are  convenient  for  hoisting  into  their  respective  positions. 
It  is  very  important  when  fixing  slate  cisterns  to  have  a  firm 
floor  on  which  they  may  rest,  or  there  will  be  difficulty  in 
making  them  water-tight.  Another  important  matter  is  to 
prevent  water  from  coming  in  contact  with  red  and  white 
lead  jointing  materials  when  the  water  is  to  be  used  for 
dietetic  purposes ;  this,  however,  can  be  done  after  the  surplus 
material  has  been  removed  by  applying  a  coat  of  hot  liquid 
pitch  over  the  joints. 

Mild  steel  and  wrought  iron  are  often  used  for  large  tanks 
which  are  required  to  resist  more  or  less  considerable  pressure. 
If  these  materials  are  unprotected  they  are  rapidly  corroded 
by  soft  water,  mild  steel  being  more  readily  attacked  than 
wrought  iron. 

Galvanised  sheet-iron  tanks  are  largely  used  for  storage 
purposes  on  account  of  their  comparative  cheapness,  and 
where  water  contains  temporary  hardness  galvanised  iron  has 
a  long  life,  and  has  no  prejudicial  effect  upon  such  water. 
Acid  waters  when  soft,  however,  corrode  iron  which  has  been 
galvanised,  the  rate  of  corrosion  being  accelerated  by  galvanic 
action.  The  action  of  certain  waters  upon  galvanised  iron 


286     DOMESTIC    SANITARY   ENGINEERING    AND    PLUMBING 

is  most   marked;  thin   sheets  being   perforated   by  corrosion 
within  three  or  four  years. 

Cast-iron  tanks  when  large  are  built  up  in  sections,  which 
as  a  rule  do  not  exceed  3  feet  square.  Flanges  are  cast 
on  the  sections,  and  these  are  occasionally  planed  to  enable 
the  joints  to  be  more  readily  made.  For  planed  joints  red 
and  white  lead  jointing  materials  are  frequently  used,  and 
for  ordinary  joints  rust  cement  is  used.  Large  tanks  require 
to  be  well  stayed,  or  they  may  fail  when  filled  with  water. 
As  a  rule  smaller  sections  than  the  size  stated  are  desirable, 
as  the  flanges  impart  stiffness  and  strength  to  the  tanks. 
In  thickness  the  plates  vary  from  f  inch  to  1  inch,  according 
to  the  pressure  they  are  required  to  withstand  and  according 
to  the  size  of  a  plate. 

Wood  cisterns  with  lead  linings  can  readily  be  made  to 
suit  any  particular  position  with  regard  to  shape,  and  lead 
is  not  affected  by  corrosion  to  the  same  extent  as  iron. 
These  cisterns  are  very  suitable  for  storing  water  for  general 
purposes,  but  when  drinking  water  is  to  be  stored  another 
form  of  lining  should  be  used. 

Copper-lined  cisterns  possess  the  same  advantages  as  those 
lined  with  lead,  excepting  that  the  former  may  be  a  little 
more  costly.  If  copper  is  tinned  the  tanks  have  a  clean 
appearance,  they  are  very  durable,  and  very  suitable  for 
storing  drinking  water  which  contains  temporary  hardness. 
Where  lead  and  copper  linings  are  used  for  wood  cisterns 
the  latter  require  to  be  substantially  constructed  to  prevent 
them  yielding  at  the  joints  by  the  continuous  thrust  of  the 
water. 

Closed  Pressure  Tanks  may  with .  advantage  be  used  in 
many  cases.  As  ball-cocks  are  discarded,  and  the  tanks  com- 
municate directly  with  the  street  mains,  the  tanks  require  to 
be  strong  enough  to  safely  resist  the  maximum  water  pressure. 
Pressure  tanks  (Fig.  186)  are  constructed  in  either  galvanised 
wrought  iron  or  in  mild  steel,  the  thickness  of  the  metals 
being  governed  by  the  diameter  of  the  tanks,  the  safe  working 
strength  of  the  material,  and  the  maximum  water  pressure. 
At  the  top  of  the  tank  a  float  valve  and  air  strainer  are 
provided,  the  latter  being  simply  an  enlargement  in  the  pipe, 


WATER   SUPPLY 


287 


AlR    5TRAIKIER 


which  is  filled  with  cotton  wool  or  other  suitable  material. 
The  float  valve  may  simply  consist  of  a  composition  ball  which 
is  buoyed  up  to  close  an 
orifice  when  the  tank  is 
full  of  water,  but  during 
the  filling  period  the  valve 
remains  open  and  air 
can  readily  escape.  At  a 
low  point  in  the  service 
pipe  a  non-return  valve  is 
fixed,  in  order  to  prevent 
water  flowing  back  from 
the  storage  tank  to  the 
street  main.  Above  the 
non-return  valve,  branches 
are  taken  from  the  service 
pipe  in  the  ordinary  man- 
ner, and  by  means  of  the 
bib  tap  shown  the  pipes 
above  that  level  can  be 
emptied  of  water. 

An  advantage  possessed 
by  the  arrangement  Fig. 
186  is  that  it  allows  water 
to  be  obtained  directly 
from  the  street  main  when 
the  pressure  at  the  point 
of  withdrawal  exceeds  that 
due  to  the  head  of  water 
in  the  tank.  When  the 
pressure  in  the  main  fails, 
water  is  available  from  the 
storage  tank. 

Safes. — When  there  is 
any  possibility  of  damage 
being  done  by  cisterns 

leaking,  it  is  usual  to  place  them  upon  lead  safes.  These 
are  simply  pieces  of  sheet  lead  which  are  turned  a  few  inches 
all  round,  so  as  to  form  a  tray  or  shallow  box.  Slate  cisterns 


FIG.  186. — Hoarding's  pressure  tank 
arrangement. 


28$     DOMESTIC   SANITARY  ENGINEERING   AND    PLUMBING 


should  always  be  fixed  upon  lead  safes,  owing  to  their  liability 
to  leak.  The  waste  pipes  from  safes  must  not  be  joined 
with  any  other  waste  pipe,  but  discharge  like  overflow  pipes 
into  the  open  air. 

Cistern  Overflows. — In  frosty  weather,  when  the  ends 
of  overflow  pipes  terminate  in  the  open  air,  a  stream  of  cold 
air  generally  flows  into  the  apartments  where  the  cisterns 
are  located,  and  aids  In  freezing  the  water  both  in  the  pipes 
and  cisterns.  To  obviate  this  the  ends  of  overflow  pipes  are 
sometimes  protected  with  light  hinged  copper  flaps,  as  in 
Fig.  187.  At  A  the  end  of  the  pipe  is  cut  splayed  with  the 
flap  resting  upon  it,  whilst  at  B  the  end  is  trimmed  that  the 


FIG.  187. — Cistern  overflow  pipes. 

hinged  flap  may  hang  a  little  open.  In  the  latter  case  the 
flap  is  intended  to  close  the  orifice  when  air  tends  to  flow 
into  the  cistern  apartment  through  the  overflow  pipe. 

Valves  for  overflows  are  made  in  different  forms  to  suit 
either  iron  or  lead  pipes ;  those  shown  are  used  for  lead  pipes, 
and  are  made  secure  by  soldering  them.  The  method  of 
fixing  the  valve  as  shown  at  A,  Fig.  187,  should  not  be  adopted, 
as  it  is  liable  to  stick,  especially  in  frosty  weather,  when  the 
overflow  may  be  rendered  inoperative. 

Overflows  should  be  large  enough  to  discharge  water  from 
cisterns  as  quickly  as  it  enters  them,  and  for  small  cisterns 
where  overflow  pipes  are  moderately  long  it  is  usually  desirable 
to  give  them  an  immediate  drop,  close  to  the  cistern,  as  in 
Fig.  188. 


WATER    SUPPLY 


289 


, 


Washouts.  —  Where  large  cisterns  are  required  it  is 
usually  essential  to  make  special  provision  for  emptying  them. 
In  Fig.  189  the  washout  is  shown  joined  with  the  overflow 
pipe,  and  it  is  controlled  with  a  clear  way  stop  valve. 

An  ordinary  stand- 
ing waste  is  given  in 
Fig.  190,  which  can  be 
removed  when  desired 
for  emptying  the  tank. 
As  it  is  necessary  for 
washouts  to  discharge 

into  a  drain  or  other  suitable  channel,  tell-tale  overflows 
should  be  arranged  to  come  into  use  before  the  larger  over- 
flow pipes.  For  example,  if  a  cistern  supply  pipe  is  4  inch 
diameter,  as  in  Fig.  189,  the  tell-tale  overflow  would  immedi- 


FIG.  188. 


FIG.  189. — Arrangement  of  pipes  in  connection  with  large  storage  tanks. 

ately  indicate  when  the  ball-cock  was  out  of  order,  whilst  the 
large  overflow  would  come  into  use  later  if  required.  In 
Fig.  190  the  cistern  is  filled  by  pumping  the  water,  and  a 
tell-tale  overflow  of  say  half  an  inch  diameter  should  discharge 
near  to  where  pumping  operations  are  conducted,  to  indicate 


290      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

when  the  cistern  is  full,  unless  some  other  form  of  indicator 
is  used. 

When  a  washout  discharges  at  a  relatively  low  point,  as  in 
Fig.  190,  the  outflow  of  water  may  be  considerably  retarded  by 
ventilating  the  vertical  stack  of  pipes  as  shown.  Precautions 
should  be  taken  to  prevent  the  trap  at  the  foot  losing  its  seal, 
and  the  pipe  on  no  account  should  directly  discharge  into  a  foul- 
water  drain. 


FIG.  190. — Large  storage  tank  showing  inlet  and  outlet  pipes. 

Fig.  189  shows  how  the  supply  and  draw-off  in  connection 
with  a  large  cistern  are  often  arranged ;  the  ball  B  closes  the 
outlet  orifice  from  the  tank  when  the  water  is  on  under  pres- 
sure, but  allows  water  to  be  withdrawn  from  the  tank  when 
the  supply  to  the  latter  fails. 

Rules  for  determining  capacities  and  sizes  of  cisterns. 
Let  G  =  capacity  of  cistern  in  gallons. 
„     I  =  length  of  cistern  in  feet. 
„    I  =  breadth  of  cistern  in  feet. 
„    li  =  depth  of  cistern  in  feet. 


WATER   SUPPLY  291 


.         .  M     (20) 

f 

and  '= 


<23> 


Should  a  storage  tank  take  an  irregular  shape,  as  in  Fig. 
191,  to  fit  some  required  position,  the  following  formulae  may 
be  used  :  — 

bxhx3%    .  .     (24) 


6  =  x  (25) 

•  (26) 


Where   n   and   o  =  the   length   of   the    short   and   long  sides 
respectively. 

Example  9.  —  If  Fig.  191  represents  the  plan  of  a  cistern 
where  n  =  3  ft.  8  in.,  0  =  4  ft.  2  in.,  width  2  ft.  4  in.;  find  its 
contents  in  gallons  if  its  depth  is  3  ft.  6  in. 


By  rule  24,  G  =  (n  +  o)  x  lx  hx  3£, 
G=7|x2Jx3Jx3i 

57575 
:   288  ' 
.-.  G  =  199fff,  or  say  200  gallons. 

Example  10.  —  Determine  the  depth  of  a  cistern  which  is 
similar  on  plan  to  Fig.  191,  to  hold  250  gallons,  where  n  = 
4  ft.  6  in.,  o  =  5  ft,  and  the  width  is  2  ft.  7|  in. 

/~i 
By  rule  26,  h  = 


250 

h  = 


9Jx2fx3i' 
1280 


,-,  h  =  3^/9-  ft->  or  3  ft.,  2|  in.  deep. 


292      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


The  actual  capacity  of  storage  tanks  with  an  intermittent 
supply  should  not  be  less  than  twenty-four  hours'  requirements, 
and  a  greater  reserve  may  be  necessary  in  certain  cases,  but 
each  case  requires  to  be  dealt  with  on  its  own  merits. 

Domestic  Filters. — If  drinking  water  is  of  doubtful  purity 
the  best  plan  is  to  boil  it.  This  method,  however,  is  not 
always  convenient  or  practicable,  and,  moreover,  water  which 
has  been  boiled  has  a  flat,  insipid  taste  on  account  of  its  lack 
of  aeration. 

Various  forms  of  household  filters  are  largely  used  for 
filtering  water,  but  very  few  are  satisfactory,  and  the  best 


III 


PLAN 


FIG.  191. — Plan  of  a  cistern. 

types  only  resist  the  passage  of  micro-organisms  for  a  limited 
period. 

Many  domestic  filters  simply  remove  suspended  and 
dissolved  organic  matter,  but  allow  the  free  passage  of  germ 
life.  As  a  rule  where  a  good  class  of  water  is  supplied  on  the 
constant  system  no  filter  should  be  used,  as  there  is  the 
possibility  of  the  filtered  water  from  a  bacterial  point  of  view 
being  inferior  in  quality  to  the  same  water  when  unfiltered. 
If,  on  the  other  hand,  a  water  supply  is  not  beyond  suspicion, 
the  filtration  of  water  for  dietetic  uses  may  be  found  desirable. 
In  the  latter  case  it  is  important  that  a  suitable  filter  be 
selected,  and  that  it  is  regularly  cleansed  and  sterilised  to 
keep  it  in  a  satisfactory  state. 


WATER   SUPPLY 


293 


Domestic  filters  may  be  divided  into  two  classes.  First, 
those  which  work  under  high  pressure ;  and  second,  those  which 
operate  with  a  low  pressure.  The  filtering  medium  may  be 
the  same  in  each  type,  the  latter  requiring  a  much  larger 
surface  of  filtering  medium. 

Amongst  the  most  reliable  domestic  filters  are  those  of  the 


VWj 


.METAL 
CASE 


Fio.  192.—  Pastenr  filter. 


FIG.  193.— Berkefeld  filter. 


Chamberland  Pasteur,  Berkefeld,  and  similar  types.  Figs. 
192  and  193  show  the  filters  mentioned,  and  in  both  cases  the 
filtering  medium  takes  the  form  of  a  cylinder  or  hollow  candle, 
fine  unglazed  porcelain  being  used  for  the  Pasteur  filter,  whilst 
compressed  silicious  earth  is  used  for  the  filtering  medium  of 
the  Berkefeld. 

The  construction   of   the   filters  is  clearly  shown,  and  in 


294     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

each  case  the  water  enters  the  metal  cylinder  and  is  forced 
under  pressure  through  the  porous  medium,  when  it  afterwards 
escapes  through  the  glazed  nozzle  outlet  in  the  case  of  the 
Pasteur,  and  through  the  bent  tube  at  the  top  of  the  filter  in 
the  Berkefeld.  The  filtering  medium  in  the  Berkefeld  is  both 
thicker  and  more  porous  than  that  in  the  Pasteur,  and  the 
former  consequently  filters  water  at  a  quicker  rate. 

To  cleanse  these  filters  the  candles  are  removed,  washed, 
sterilised  by  boiling  them,  and  afterwards  replaced.  Owing  to 
the  slow  rate  of  filtration  by  a  single  Pasteur  filter  a  small 
reserve  of  filtered  water  is  desirable.  For  this  purpose  a  glass 
or  stoneware  jar,  which  is  fixed  immmediately  beneath  and 
connected  with  the  filter,  is  generally  adopted.  Water  may 
then  be  withdrawn  directly  from  the  receiver,  but  precautions 
are  necessary  to  guard  against  contamination,  as  filtered  water 
readily  absorbs  any  gases  to  which  it  may  be  exposed. 

For  low  pressure  filters  of  the  Pasteur  and  Berkefeld  types, 
several  candles  are  arranged  inside  a  large  metal  casing  or 
cistern,  the  candles  being  joined  to  one  common  channel  into 
which  the  filtered  water  escapes.  As  a  number  of  joints  are 
necessary  with  this  arrangement,  there  is  a  possibility  of  some 
defect  occurring  through  which  unfiltered  water  may  gain 
access  to  that  which  has  been  filtered. 

Domestic  filters  to  be  satisfactory  must  be  simply  con- 
structed, and  admit  of  being  readily  taken  to  pieces  for 
cleansing  purposes.  After  a  filter  has  been  in  use  for  some 
time,  its  filtering  capacity  is  greatly  reduced  owing  to  the 
choking  of  the  pores,  but  its  normal  rate  may  be  again  restored 
by  thoroughly  cleansing  it. 

Water  Fittings. — Taps,  cocks,  cranes,  or  valves  may  be 
roughly  divided  into  three  classes  : — 

1.  Those  which  automatically  regulate  the  outflow  of  water. 

2.  Those  which  are  operated  by  hand. 

3.  Those  which  are  semi-automatic  in  action. 

To  the  first  class  belong  ball-cocks  which  are  opened  and 
closed  by  the  falling  and  rising  water  in  a  cistern.  To  the 
second  class  the  various  forms  of  screw-down  and  plug  taps 
belong.  To  the  third  class  belong  those  which  are  opened  by 
hand,  but  are  automatically  closed  either  by  the  aid  of  springs 


WATER    SUPPLY  295 

or  by  the  water  pressure,  or  by  means  of  a  weighted  lever. 
As  a  large  variety  of  fittings  belong  to  each  class,  further  sub- 
division becomes  necessary  in  order  to  compare  their  relative 
merits  and  defects. 

Bail-Cocks. — These  taps,  which  belong  to  the  first  class , 
may  be  subdivided  into  high  and  low  pressure  forms.  High 
pressure  ball  -  cocks  have  often  restricted  water-ways,  and 
where  the  latter  are  fairly  large  the  levers  are  frequently 
compounded.  Low  pressure  ball-cocks  have  large  water-ways, 
and  may  either  be  constructed  upon  the  equilibrium  principle 
or  with  simple  direct  acting  levers. 

Much  annoyance  and  inconvenience  are  caused  from  time 
to  time  by  fixing  unsuitable  ball-cocks  in  cisterns.  Very 
frequently  a  form  of  high-pressure  tap  is  connected  with  a  low- 
pressure  service,  with  the  result  that  the  cistern  takes  too  long 
to  fill.  For  flushing  cisterns  in  connection  with  w.c.'s  it  is 
specially  necessary  that  they  fill  rapidly,  but  this  can  only  be 
accomplished  by  the  selection  of  suitable  taps  for  the  pressure 
at  disposal. 

Should  a  low-pressure  ball-cock  be  fixed  on  a  high-pressure 
service,  the  former  will  either  be  often  out  of  order,  or  rattling 
sounds  will  be  caused,  due  to  the  oscillation  of  the  lever  when 
the  tap  is  nearly  closed.  The  latter  action  under  certain 
conditions  is  readily  brought  about,  owing  to  the  force  which 
operates  to  close  the  tap  not  sufficiently  exceeding  that  which 
tends  to  open  it.  When  oscillation  of  a  lever  has  commenced 
the  water  pressure  is  increased  to  a  more  or  less  extent, 
according  to  the  amount  of  concussion  produced  by  the  quick 
successive  opening  and  closing  of  the  tap. 

Two  common  and  good  types  of  ball-cocks  are  given  in 
Figs.  194  and  195,  but  they  are  only  suitable  on  account  of 
their  restricted  outlets  for  high-pressure  services.  In  con- 
struction the  principle  is  the  same  in  each  case,  their  difference 
being  in  the  arrangement  of  the  plug  or  piston  C,  which 
contains  the  washer.  In  Fig.  194  the  piston  moves  horizon- 
tally, whilst  that  of  Fig.  195  has  a  vertical  motion,  the  water 
escaping  from  the  latter  by  side  passages  which  are  not  shown 
in  the  figure. 

When  water  is  under  considerable  pressure  the  ball-cocks 


296      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

shown  are  somewhat  noisy  in  action,  especially  when  they  are 
nearly  closed  owing  to  the  water  issuing  with  considerable 
velocity  through  the  contracted  orifice.  This  objection, 


FIG.  194. — High-pressure  ball-cock. 

however,  can  be  overcome  to  a  great  extent  by  attaching  to 
the  outlet  P  of  Fig.  194  a  short  length  of  tube  in  order  that  the 
point  of  escape  may  be  submerged.  Upon  reference  to  Fig. 
195  it  will  be  observed  that  it  does  not  admit  of  a  tube  being 
readily  attached,  and  this  is  the  chief  drawback  of  this  pattern 
of  ball-cock. 


FIG.  195. — High-pressure  ball-cock. 

A  patented  ball-cock  is  given  in  Fig.  196,  and  in  con- 
struction the  part  containing  the  valve  is  similar  to  that  in 
Fig.  195,  excepting  that  the  orifice  0  is  larger.  In  Fig.  196 
the  additional  power  which  is  necessary  to  compensate  for  the 
larger  valve  orifice  is  obtained  by  compounding  the  levers  as 


WATER   SUPPLY 


297 


shown.  The  regulating  screw  S  is  an  advantage,  for  by  its 
means  the  ball-cock  can  be  adjusted  with  precision  without 
resorting  to  the  practice  of  bending  the  levers.  It  will  be 
observed  that  the  mechanical  advantage  of  lever  A  is  con- 
centrated, and  operates  at  the  adjusting  screw  S,  which  forms 
the  end  of  the  long  side  of  lever  B.  From  a  practical  point 
of  view  the  advantage  derived  by  compounding  the  levers 
of  ball-cocks  is  very  limited,  and  therefore  the  size  of  the  valve 
orifice  for  high  pressures  is  also  limited. 

The  full -way  equilibrium  valve  Fig.  197  is  well  adapted  for 
low  pressures.  In  construction  it  differs  considerably  from  the 
foregoing,  inasmuch  as  the  water  pressure  is  utilised  in  addition 


FIG.  196. — The  "Hiorlo"  ball-cock  with  compounded  lever. 

to  the  float  and  lever  for  closing  the  valve.  At  the  upper  pan 
of  Fig.  197  a  cup-leather  C  is  provided  to  make  the  valve 
water-tight  at  that  point.  The  pressure  of  the  water  is  exerted 
both  on  the  cup-leather  C  and  the  valve  V,  and  as  their  surfaces 
in  the  case  shown  are  equal,  the  total  pressure  acting  upon  each 
surface  when  the  valve  is  closed  is  also  equal ;  under  these 
conditions  equilibrium  is  only  destroyed  by  the  weight  of  the 
ball  and  lever  when  the  water  level  begins  to  sink. 

For  high-pressure  services,  cocks  like  Fig.  197  are  not 
suitable,  as  they  are  liable  to  produce  more  or  less  concussion 
when  nearly  closed.  A  drawback  associated  with  ball-cocks 
which  have  cup-leathers  is  their  liability  to  leakage  should 
the  cup-leathers  get  hard  and  dry  through  the  turning  off  of 
water  for  prolonged  periods. 


298      DOMESTIC   SANITARY   ENGINEERING    AND   PLUMBING 

Of  the  ball-cocks  shown,  it  will  be  noticed  that  only  in  Fig. 
197  does  the  water  pressure  play  any  part  in  closing  them,  but 
on  the  contrary  the  pressure  of  the  water  in  Figs.  194  to  196 
is  always  acting  to  open  them.  Ball-cocks  are,  however,  made 
which  close  with  the  water  pressure,  but  these  are  often 
troublesome  for  high-pressure  services  unless  a  special  form 
of  construction  is  introduced  to  prevent  concussion. 

Taps  of  the  second  class  may  be  subdivided  into  screw-down 
and  plug  forms.  Of  the  screw-down  class  there  are  many 
kinds,  both  of  bib  and  stop-cocks,  but  the  main  principle  is 
common  to  all. 


FIG.  197. — Equilibrium  ball-cock. 

A  section  through  a  bib  tap  is  shown  in  Fig.  198.  In  a 
good  class  of  tap  the  seating  should  be  wide  and  a  little  raised 
in  order  to  form  a  good  bearing  for  the  valve;  the  screw 
part  of  the  tap  at  its  lower  point  should  be  enlarged  as  at  E, 
so  as  to  distribute  pressure  over  the  greater  portion  of  the 
loose  valve  when  closing  the  tap.  For  a  tap  to  be  durable  it 
requires  to  be  strongly  made,  and  especially  where  high 
pressures  are  concerned.  A  better  method  of  testing  water 
fittings  to  that  frequently  adopted  by  Water  Companies  is 
desirable,  as  many  of  the  jerry  made  fittings  which  are  put 
upon  the  market,  aithough  capable  of  withstanding  a  pressure 


WATER    SUPPLY  299 

test  when  they  are  new,  fail  after  being  in  use  for  a  com- 
paratively short  time. 

For  water  fittings  hard  brass  is  a  suitable  alloy  where 
water  contains  temporary  hardness,  but  for  soft  acid  waters 
gun-metal  fittings  should  be  used. 

A  clear-way  screw-down  cock,  Fig.  199,  is  very  suitable 
for  low  pressures,  as  it  possesses  no  loose  valve  which  is  liable 
to  stick.  It  is  also  suitable  for  high  pressure  services. 

Plug  taps,  Fig.  200,  are  often  used  for  both  bib  and  stop- 


FIG.  198. — High-pressure  screw-down  cock. 

taps  where  the  water  pressure  is  low,  as  well  as  for  under- 
ground stop-cocks  on  high-pressure  services.  Plug  taps  are 
very  suitable  for  joining  directly  with  cisterns  to  control  the 
smaller  draw-off  pipes.  These  taps  are  liable  to  stick  when 
not  in  regular  use,  although  this  can  be  avoided  to  a  great 
extent  by  properly  greasing  them  when  they  are  fixed ;  more- 
over, when  plug  taps  are  in  accessible  positions  there  is  very 
little  difficulty  in  loosening  the  plugs  which  may  have  tem- 
porarily become  fast. 

Bib  taps  of  the  plug  type,  when  under   a  more  or  less 
considerable   head   of   water,   subject   pipes    and    fittings    to 


300      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


unnecessary  strain   by  being   too   quickly   closed.     Bib   taps 
when  in  constant  use  work  loose,  and  by  suddenly  arresting 


FIG.  199.  —  Fullway  high-pressure  screw-down  valve. 

the  How  of  water  the  pressure  due  to  shock  is  often  consider- 
able, and  may  rise  to  many  times  that  which  is  due  to  the 
statical  head  of  water. 

The  quick  clos- 
ing of  plug  bib  taps 
has  often  been 
responsible  for 
damaged  pipes  ; 
sudden  shocks  are 
far  more  detrimen- 
tal than  a  constant 
strain  due  to  high 
pressure.  When  a 
quick-closing  tap 

is    fixed   t0   a 


Fir,  200.  -Plug  cock. 

the  part  where  the 

greatest  pressure  due  to  concussion  occurs  is  near  the  end  of 
the  pipe.  Bends  in  pipes  influence  the  result,  but  as  a  rule 
the  pressure  due  to  any  specific  shock  at  different  parts  of  a 


WATER   SUPPLY  301 

pipe  diminishes  rapidly  from  the  end.  With  regard  to  the 
inte'nsity  of  pressure  due  to  shock,  that  will  depend  upon  the 
normal  pressure  of  water  at  the  point  under  consideration,  the 
pressure  during  the  period  when  the  tap  is  opened,  and  the 
rate  at  which  the  tap  is-closed. 

Screw-down  taps  are  largely  adopted  in  buildings,  as  these 
can  be  easily  repaired,  and  as  they  are  slowly  closed  concus- 
sion is  reduced  to  a  minimum. 

A  certain  amount  of  care  is  essential  when  fixing  plug  taps. 
Many  plumbers  when  soldering  a  plug  tap  to  a  lead  pipe  first 
remove  the  plug  from  the  body  of  the  tap,  in  order  to  more 
quickly  get  up  the  "  heat "  for  wiping  the  joint ;  when  the 
work  is  complete,  and  the  water  is  turned  on,  it  is  often  found 
that  the  tap  leaks,  and  to  remedy  the  defect  "  grinding  in"  is 
necessary.  Had  the  plug  been  left  in  the  tap  during  the 
wiping  process  it  is  very  probable  that  the  leakage  referred  to 
would  not  have  occurred.  The  reason  for  this  assumption  is, 
that  as  the  temperature  of  the  whole  mass  of  metal  has  been 
raised,  the  rate  of  expansion  would  be  practically  uniform,  and 
upon  cooling  the  rate  of  contraction  would  also  be  uniform  for 
the  whole  mass.  On  the  other  hand,  where  the  body  of  a  tap 
has  been  raised  and  cooled  through  a  big  range  of  temperature, 
and  the  plug  has  not  been  subjected  to  a  like  action,  it  is 
quite  feasible  for  the  ground  surfaces  to  be  affected  owing  to 
the  rate  of  contraction  not  being  quite  equal  to  the  rate  of 
expansion.  The  above  description,  however,  more  particularly 
applies  to  the  cheaper  class  of  taps,  many  of  which  are 
deficient  in  substance,  and  where  the  quality  of  the  alloy  is 
not  all  that  can  be  desired. 

Spring  taps,  which  come  within  the  range  of  the  third  order, 
may  be  subdivided  into  quick  and  slow-closing  types.  Quick- 
action  spring  taps  cause  a  great  amount  of  concussion,  and, 
like  plug  taps,  are  not  suitable  for  draw-off  taps  on  high- 
pressure  services.  The  primary  object  of  self-closing  taps 
is  to  reduce  waste  of  water,  but  in  practice  more  water  is 
frequently  wasted  by  their  use  than  with  any  other  form  of 
tap,  owing  to  their  being  often  out  of  repair. 

A  quick-closing  spring  tap  is  given  in  Fig.  201.  It  will 
be  noticed  that  the  valve  V  opens  against  the  water  pressure, 


302      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

and  therefore  the  latter  is  available,  in  addition  to  the  spring 
S,  for  closing  the  tap.  The  combined  forces  of  course  require 
to  be  overcome  to  open  the  tap.  This  form  of  cock,  however, 
will  produce  water-hammer  in  pipes  when  the  press-knob  is 
released,  owing  to  the  sudden  closing  of  the  tap ;  where  the 
water  pressure  is  moderately  high  the  valve  will  rebound 
from  its  seating,  and  a  number  of  successive  shocks  may  be 
produced  before  the  tap  is  properly  closed. 

To  render  a   self-closing    tap  non-concussive  its  rate  of 


FIG.  201. — Defective  form  of  self-closing  tap. 

closing  requires  to  be  regulated.  In  Fig.  202  a  slow-closing 
and  non-concussive  tap  is  shown  by  Glenfield  and  Kennedy  Ltd., 
which  operates  in  the  following  manner:  Under  normal 
conditions,  when  the  water  is  on  under  pressure,  the  forces 
exerted  by  the  water  on  both  the  under  and  upper  surfaces  of 
the  piston  P  are  equal,  and  the  valve  x  is  pressed  upwards 
by  the  water  pressure  beneath  it  as  well  as  by  the  force  of 
the  spring.  At  the  under  side  of  piston  P  a  small  valve  y 
is  provided,  which  is  opened  by  means  of  a  thin  spindle  which 
passes  through  the  tubular  rod  R  to  the  press-knob  at  the  top 
of  the  tap.  The  use  of  the  small  valve  enables  the  tap  to  be 


WATER   SUPPLY 


303 


the  more  easily  opened,  as  the  resistance  offered  by  the  water 
to  the  opening  of  the  valve  is  directly  proportional  to  its 
sectional  area.  For  example,  if  the  diameter  of  a  valve  is  f  of 
an  inch,  and  that  of  another  f  of  an  inch,  the  force  to  open  the 
former  would  be  four  times  greater  than  that  required  to  open 
the  smaller  valve. 

When  force  is  applied  on  the  press-knob  the  small  valve 
y  is  first  opened;  this  releases  the  internal  pressure  in 
cylinder  C,  by  allowing  the  water  to  escape  through  the 


FIG.  202. — Glenfield  and  Kennedy's  non-concussive  self-closing  tap. 

hollow  rod  K  to  the  outlet  of  the  tap.  The  differential 
pressure  thus  produced  on  the  upper  and  under  surfaces  of 
piston  P  allows  the  larger  valve  x  to  be  readily  opened, 
when  the  water  freely  escapes.  To  enable  valve  x  to  be 
slowly  closed  water  is  slowly  admitted  into  C,  either  through 
a  small  orifice  at  the  top  of  the  piston  or  by  leakage  at  its 
sides ;  upon  the  press-knob  being  released  the  small  valve  y 
is  immediately  closed,  and  as  water  gradually  exerts  pressure 
on  the  under  side  of  piston  P  the  valve  begins  to  close. 
The  sudden  closing  of  x  is  prevented  by  the  downward  force 


304      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

of  water  on  the  top  of  the  piston,  and  by  equal  pressures 
on  both  the  under  and  upper  surfaces  being  delayed  through 
a  given  interval  of  time. 

Slow-action,  self-closing  taps  which  are  similar  in  prin- 
ciple to  Fig.  202  may  be  used  for  either  low  or  high-pressure 
services,  but  the  strength  of  the  springs  should  be  adjusted 
according  to  the  intensity  of  the  pressure.  For  low  pressures 
a  moderately  strong  spring  is  essential  to  overcome  resistance 
offered  by  the  piston  P,  whilst  for  high  pressures  a  much 
weaker  spring  is  desirable,  as  frictional  resistance  is  of  less 
importance.  A  strong  spring  has  the  effect  of  making  the  tap 
more  difficult  to  open. 

Water-Hammer  and  Other  Noises  in  Pipes. — In  describing 
the  different  forms  of  taps,  reference  has  been  made  to  those 
which  are  liable  to  produce  shock,  and  by  water-hammer  is 
understood  the  sharp  rapping  sounds  which  are  due  to 
shock.  Other  noises  occur  in  water  pipes,  such  as  buzzing 
sounds,  but  these  differ  from  water-hammer,  as  the  latter  is 
accompanied  by  increased  pressure,  whilst  the  former  are 
simply  due  to  water  flowing  with  a  high  velocity  through  an 
irregular  or  contracted  orifice,  and  are  not  accompanied  with 
any  excess  of  the  normal  pressure. 

A  buzzing  sound  may  be  produced  when  a  screw-down 
tap  is  nearly  closed,  and  where  the  valve  is  rather  loose  or 
does  not  close  evenly  on  its  seat ;  if  water  has  greater  freedom 
to  flow  under  one  side  more  so  than  another,  a  rotary  action 
is  imparted  to  the  loose  valve,  and  thus  the  buzzing  begins. 

Whistling  sounds  are  occasionally  produced  by  ball-cocks 
when  nearly  closed,  but  where  these  sounds  are  objectionable 
ball-cocks  should  be  used  which  have  submerged  outlets. 

The  rattling  or  clicking  sounds  which  are  produced  by 
automatic  and  semi-automatic  taps  are  a  form  of  water- 
hammer,  but  shock  of  much  less  intensity  accompanies  these 
when  compared  with  that  of  a  pronounced  water-hammer. 

To  remedy  a  case  of  water-hammer  its  cause  should  first 
be  ascertained.  If  a  certain  type  of  ball-cock  is  responsible 
for  it,  it  may  be  necessary  to  change  the  cock  for  another 
type.  Should  quick-closing  bib  taps  be  the  cause  of  water- 
hammer,  then,  if  practicable,  they  should  be  replaced  with  the 


WATER    SUPPLY 


305 


screw-down  type ;  but  if  for  some  reason  quick-closing  taps 
must  remain,  the  only  alternative  is  to  provide  some  form  of 
cushion  on  which  the  shock  may  be  absorbed  or  relieved. 
For  this  purpose  air-vessels  are  the  most  satisfactory  fittings, 
provided  they  are  suitably  placed. 

Air-vessels    should    be    fixed    to    the    pipes    where    the 


ID) 


FIG.  203. 


Air-vessels  for  water  pipes. 


Fio.  204. 


maximum  pressure  due  to  concussion  occurs ;  they  must  be  of 
sufficient  strength  and  of  ample  size. 

In  Fig.  203  two  different  methods  of  fixing  air-vessels 
are  given  where  the  flow  of  water  is  in  a  downward  direction. 
The  air-vessels  are  fixed  close  to  the  source  of  concussion, 
the  plug  tap  in  A  being  joined  directly  with  the  air-vessel, 
whilst  in  B  the  air-vessel  is  connected  with  the  side  of  the 
pipe  immediately  above  the  tap.  At  C,  Fig.  204,  an  air-vessel 
is  fixed  at  the  head  of  the  pipe,  and  at  D  of  the  same  figure 
20 


306      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


at  some  intermediate  point.  If  the  air-vessel  in  D  is  some 
distance  removed  from  the  cause  of  water-hammer,  it  will 
not  effectively  cure  the  latter  although  it  will  diminish  the 
shock. 

To  provide  an  effective  cushion  of  air,  air-vessels  should 
not  be  less  in  diameter  than  twice  that  of  the  pipes  to  which 

they  are  to  be  attached,  and  not 
less  than  18  inches  in  length. 

Instead  of  using  a  special 
air-vessel,  the  end  of  a  pipe  is 
sometimes  bent  upwards  so  as 
to  serve  the  same  purpose,  but 
in  the  latter  case  the  capacity 
of  the  pipe  is  too  small  to  be 
effective. 

It  will  be  occasionally  found 
that  when  a  quick-closing  tap  is 
fixed  on  a  branch,  as  in  Fig.  205, 
a  ball  tap  at  a  higher  point,  and 
which  is  connected  with  the  same 
service  pipe,  is  caused  to  vibrate 
and  to  produce  sharp  clicking 
sounds  when  the  bib  tap  is  rapidly 
closed.  The  concussion  in  the 
branch  may  be  relieved  by  an 
air-vessel  as  shown,  but  as  the 
pressure  in  pipe  M  rapidly  falls 
when  the  bib  tap  is  opened,  there 
is  also  a  momentary  gain  of  pres- 
sure in  the  same  pipe  when  the 

tap  is  quickly  closed.  The  fixing  of  an  air-vessel,  however,  in 
the  immediate  neighbourhood  of  a  ball-cock  may  tend  to  acceler- 
ate water-hammer  rather  than  to  prevent  it.  For  an  air-vessel 
to  be  effective  in  one  case  and  not  in  another  may  at  first 
appear  anomalous,  but  when  the  difference  in  construction  of 
ball  and  quick-closing  taps  is  taken  into  account  the  anomaly 
disappears.  There  is  no  common  cure  for  all  cases  of  water- 
hammer,  and  each  case  requires  to  be  considered  on  its  own 
merits. 


FIG.  205. — Air-vessels  for  water 
pipes. 


WATER    SUPPLY  307 

So  violent  sometimes  are  the  shocks  produced  by  water- 
hammer  that  the  sound  is  transmitted  long  distances. 
When  several  houses  are  supplied  by  one  common  service 
pipe,  it  is  no  unusual  thing  for  water-hammer  in  one  house  to 
be  heard  in  all  the  others. 

Under  certain  conditions  a  quick-action  tap  may  produce 
little  or  no  concussion,  but  this  largely  depends  upon  the  size 
of  the  pipe  and  the  position  where  the  tap  is  joined.  Thus, 
if  a  plug  stop-cock  is  connected  directly  with,  or  close  to  a 
water  main,  the  quick  closing  of  the  tap  would  not  greatly 
affect  either  the  pressure  at  the  tap  or  that  in  the  water 
main.  The  reason  for  this  is  rendered  clear  when  the  short 
distance  from  the  plug  of  the  tap  to  the  main,  and  the  relative 
velocities  of  the  water  in  the  service  pipe  and  in  the  main, 
are  taken  into  account. 

Suppose,  for  example,  a  tapping  main  is  6  inches  diameter, 
and  the  orifice  in  the  plug  of  a  tap  1  inch  diameter,  and  that 
the  tap  is  joined  directly  to  the  main.  Taking  the  velocity 
of  the  water  through  the  tap  at  9  feet  per  second,  the  velocity 


in   the  6-inch    main    to  yield  this  would  be   —  ~-  =  \  ft.  or 

o2 

3  inches  per  second.  Thus  the  concussion  which  would  occur 
in  a  main  by  suddenly  arresting  such  a  low  velocity  would  not 
be  of  much  account.  It  is  very  different,  however,  in  the  case 
of  long  pipes,  where  the  cocks  are  of  the  same  size,  for  then 
the  velocity  of  flow  through  each  is  equal,  and  the  greater 
the  velocity  the  greater  the  shock  when  the  flow  is  abruptly 
stopped. 


CHAPTEK   XI 
APPLIANCES   FOR   RAISING   WATER 

HYDKAULIC  rams  and  pumps  are  largely  used  for  raising  water 
from  a  low  to  a  higher  elevation,  but  the  use  of  the  former  is 
limited  when  compared  with  the  latter  appliances. 

Pumps  take  various  forms,  but  they  may  be  classified  as 
follows : — 

1.  Single  action  lift  pumps. 

2.  Double  action  lift  pumps. 

3.  Lift  and  force  pumps. 

4.  Plunger  or  force  pumps. 

5.  Air-liffe  pumps. 

6.  Centrifugal  pumps. 

Numbers  3  and  4  may  be  either  single  or  double  acting 
forms,  and  they  may  also  be  arranged  to  work  with  one,  two, 
or  three  barrels.  Those  in  5  and  6  scarcely  come  within  the 
scope  of  this  work,  and  in  consequence  they  will  only  be  briefly 
dealt  with. 

Lift  Pumps. — When  an  ordinary  lift  pump  is  used  for 
raising  water  from  a  well,  the  height  to  which  water  can  be 
raised  is  limited  by  atmospheric  pressure.  The  pressure  of 
the  atmosphere  varies  with  altitude  and  with  different  weather 
conditions,  but  taking  the  normal  atmospheric  pressure  at  sea 
level  to  be  14|  Ib.  per  sq.  inch,  this  is  equivalent  to  the 
pressure  exerted  by  a  column  of  wrater  which  is  34  feet  in 
height.  As  a  margin  of  power  must  be  on  the  side  of  the 
atmosphere  to  overcome  internal  resistances  of  a  pump,  the 
maximum  height  to  which  water  can  be  raised  by  a  lift  pump 
is  about  28  to  30  feet.  This  height  should  be  measured  from 
the  lowest  water  level  to  the  top  of  the  bucket  or  plunger 
when  the  pump  handle  is  down. 


APPLIANCES    FOR    RAISING    WATER 


309 


Iron  lift  pumps  may  take  the  form  shown  in  Fig  206. 
They  may  be  fixed  to  a  wall  or  wooden  plank,  or  be  made 
taller  than  the  one  shown,  and 
supported  by  bolting  them  to 
stone  flags. 

The  bucket  B  in  Fig.  206  is 
made  water-tight  at  its  sides 
with  a  cup-leather,  and  a  valve 
x  is  arranged  to  open  when  the 
bucket  is  descending  and  to  close 
when  being  raised.  The  valve 
V  holds  up  the  water  in  the 
pump,  and  prevents  its  returning 
into  the  suction  pipe  when  the 
bucket  is  descending.  The  action 
of  the  pump  is  as  follows :  When 
the  bucket  descends,  the  upper 
valve  opens,  and  water  escapes 
above  it ;  upon  the  bucket  being 
raised,  the  water  above  it  is  dis- 
placed through  the  outlet,  and 
at  the  same  time  atmospheric 
pressure  forces  up  the  water 
through  the  suction  pipe  to  fill 
the  space  through  which  the 
bucket  has  moved. 

The  term  "  suction  "  pipe  is 
often  misleading,  as  it  indicates 
that  the  water  is  raised  by 
suction  instead  of  being  due  to 
displacement  by  atmospheric 
pressure. 

When  an  iron  pump  is  used 
the  working  part  of  the  barrel 
should  be  fitted  with  a  thin 


FIG.  206.— Lift  pump. 


gun-metal  lining,  in  order  to  preserve  the  cup-leather  and  to 
keep  the  pump  in  good  order. 

Suction  Pipes. — For   economical  considerations,  and  also 
for  convenience,  suction  pipes  are  usually  smaller  than  the 


310      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

barrels  of  the  pumps.  The  effect  of  reducing  the  sizes  of 
suction  pipes  is  to  increase  frictional  resistances,  as  the  water 
has  to  flow  through  them  at  a  greater  velocity  than  through 
the  barrels  of  the  pumps.  If,  for  example,  a  pump  is  of  4  inches 
diameter,  and  its  suction  pipe  of  2  inches  diameter,  the  velocity 
through  the  latter  would  be  4  times  that  through  the  barrel  of 
the  pump. 

Under  ordinary  circumstances,  where  a  suction  pipe  is  not 
very  long,  and  where  a  pump  is  worked  at  a  slow  rate,  a 
suction  pipe  whose  diameter  is  half  that  of  the  pump  will  give 
satisfaction.  On  the  other  hand,  should  a  suction  pipe  be  very 
long,  it  should  be  increased  by  one  size,  and  the  area  of  the  re- 
taining valve  should  also  be  as  large  as  practicable.  Suction 
pipes  when  subject  to  corrosion  should  also  be  of  a  larger  size. 

Frequently  when  a  suction  pipe  is  long  a  pump  is  difficult 
to  work.  The  cause  of  this  may  be  due  to  the  suction  pipe 
being  too  small,  or  to  other  restricted  water  passages,  such  as 
the  lower  end  of  the  pipe  being  partially  choked.  Should  the 
flow  of  water  through  a  suction  pipe  be  unduly  retarded,  the 
action  of  the  bucket  will  resemble  that  of  a  spring  when  in 
tension.  If  the  flow  to  a  pump  is  not  as  free  as  the  rate  of  dis- 
placement from  it,  a  partial  vacuum  is  created,  and  the  bucket 
will  endeavour  to  fly  back  to  restore  equilibrium  when  the 
handle  is  quickly  released. 

The  greatest  power  when  pumping,  is  required  at  the 
commencement  of  the  stroke,  as  the  inertia  of  the  water 
requires  to  be  overcome  before  the  latter  can  be  put  into 
motion.  With  a  single  action  pump  like  Fig.  206  the  power 
to  move  the  piston  will  vary  with  the  upward  and  the  down- 
ward strokes,  as  well  as  at  the  commencement  of  the  stroke. 

To  put  water  in  motion  in  long  suction  pipes  the  power 
required  may  be  much  reduced  by  fixing  air-vessels  immediately 
beneath  the  retaining  valves,  as  in  Fig.  207.  In  form,  the  air- 
vessel  for  a  suction  pipe  may  be  similar  to  that  of  an  ordinary 
air-vessel,  but  instead  of  its  contained  air  being  in  a  state  of 
compression  it  is  more  or  less  extended.  If  it  is  assumed  that 
a  pump  is  being  worked  which  has  an  air-vessel  attached,  as 
in  Fig.  207,  at  the  beginning  of  each  stroke  the  rising  water 
will  compress  the  confined  air  to  a  certain  extent,  but  at  the 


APPLIANCES    FOR    RAISING    WATER 


311 


completion  of  the  stroke  the  column  of  water  in  the  suction 
pipe  will  tend  to  sink  a  little,  and  to  extend  the  air  in  the 
vessel.  This  has  the  effect  of  providing  a  force  with  a  spring- 
like action  which  pulls  against  the  water,  and  so  makes  it  ready 
to  be  put  into  motion  when  commencing  to  work  the  pump. 

Occasionally  a  non-return  valve  is  fixed  in  a  suction  pipe 
immediately  above  the  water-line  of  a  well  or  tank  from  which 
the  water  is  pumped.  Such  a  valve  is  useful  in  certain  cases, 
where  the  retaining  valve  of  a  pump  cannot 
be  depended  upon,  or  where  two  pumps  in 
different  situations  are  connected  with  one 
suction  pipe.  A  non-return  valve,  however, 
should  not  be  used  for  a  suction  pipe  which 
has  an  air-vessel  attached,  or  the  latter 
would  be  rendered  useless,  and  in  consequence 
the  pump  would  be  more  difficult  to  work. 
Suction  pipes  should  be  arranged  so  that  air 
cannot  lodge  in  them,  and  this  can  be  done 
by  making  them  rise  to  the  pumps  for  the 
whole  of  their  length. 

/•5ucTioM  PIPE 


FIG.  207. — Suction  pipe  with  air-vessel  attached. 


Pumps  for  Deep  Wells. — Where  the  vertical  distance 
between  the  lowest  water  level  in  a  well  and  the  top  of  a  pump 
bucket  exceeds  say  30  feet,  the  working  part  of  a  pump  barrel 
will  require  to  be  fixed  in  the  well  in  order  that  water  may  be 
raised.  For  a  well  of  great  depth  the  suction  pipe  should  be 
made  as  short  as  practicable,  or,  in  other  words,  the  working 
part  of  a  barrel  should  not  as  a  rule  be  more  than  about  15 
feet  above  the  normal  water-line,  when  the  lowest  water  level 
is  only  about  5  feet  less.  In  certain  wells,  where  the  water 
level  is  lowered  by  pumping  to  a  considerable  extent,  it  may  be 
necessary  for  the  working  part  of  the  barrel  to  be  submerged 
when  the  highest  water-line  is  reached. 


312      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


When  a  single  action  pump  is  used  for  raising  water  from 

a  well  of  moderate  depth, 
and  where  hand  power  only 
is  available,  the  size  of  a 
pump  requires  to  be  limited. 
A  type  of  pump  which 
has  often  been  used  in 
country  districts  for  wells 
which  vary  in  depth  from 
20  to  80  feet  is  given  in 
Fig.  208.  The  barrel  and 
suction  pipe  are  of  lead,  the 
former  being  4  inches  and 
the  latter  2  inches  diameter. 
To  the  upper  end  of  the 
pump  barrel  a  lead  head  is 
soldered,  and  in  turn  a  lead 
spout  is  soldered  to  the 
head.  It  will  be  observed 
that  the  barrel  stands  up 
inside  the  head  at  H  in 
front  of  the  spout,  whilst 
towards  the  back  of  the 
head  it  is  cut  away.  This 
arrangement  prevents  the 
pump  being  damaged  by 
pieces  of  stick,  or  by  small 
stones  being  passed  through 
the  spout  and  into  the 
barrel  by  children ;  at  the 
same  time  the  water  can 
freely  escape  from  the  back. 
The  pump  rod,  which  is 
generally  of  wood,  passes 
through  the  barrel,  and  to 

FIG.  208.— Lead  pump  for  deep  wells.       its    upper     end     the     guide 

arrangement     is    attached, 

whilst  to  the  lower  end  the  iron- work  of  the  bucket  is  fixed. 
The  wood  rods  are  made  in  convenient  lengths  for  handling, 


APPLIANCES    FOR    RAISING    WATER  313 

and  are  spliced  together  as  they  are  passed  into  the  pump 
barrel.  Splices  require  to  be  well  formed  to  prevent  them 
failing,  and  to  admit  of  the  different  lengths  of  rod  being 
readily  taken  apart.  A  copper  cylinder  C  should  be  fixed 
immediately  above  the  access  opening  A,  in  order  to  provide  a 
suitable  place  in  which  the  bucket  can  work.  A  non-return 
valve  is  provided  at  V,  and  this  can  be  renewed  or  repaired  by 
means  of  the  opening  at  A. 

There  is  no  difficulty  in  balancing  a  handworked  pump  like 
Fig.  208,  as  the  wood  rods  are  buoyed  up  with  the  water 
and  the  pump  is  double  acting  in  principle;  that  is,  it  will 
raise  water  with  both  its  upward  and  its  downward  strokes. 
A  casual  glance  at  the  pump  may  not  make  this  clear,  but 
when  it  is  considered  that  at  each  downward  stroke  a  volume 
of  water  must  be  displaced  by  the  rod,  then  obviously  the 
upward  stroke  must  displace  that  much  less.  By  making  the 
diameter  of  the  pump  rod  equal  in  area  to  half  that  of  the 
barrel,  the  volume  of  water  due  to  the  full  length  of  the  stroke 
may  be  equally  divided  and  displaced  by  the  upward  and 
downward  motion  of  the  rod. 

A  pump  similar  to  Fig.  208  can  be  worked  with  a  given 
power  which  would  be  totally  indequate  to  operate  one  with 
iron  rods,  provided  the  conditions  with  regard  to  size,  and  the 
height  through  which  water  requires  to  be  raised,  are  equal. 

For  supporting  lead  pumps  oak  bearers  are  often  em- 
ployed ;  these  are  fixed  on  each  side  of  the  pump  barrel,  and 
pieces  of  oak  board  which  have  been  cut  to  fit  around  the 
barrel  are  nailed  across  the  bearers.  At  a  support  two  lengths 
of  barrel  are  joined,  and  a  lead  flange  is  fixed  upon  the 
woodwork  and  soldered  to  the  barrel.  A  convenient  length 
for  lead  pump  barrel  is  8  feet,  and  such  a  length  can  be 
properly  supported  in  the  manner  described. 

In  this  class  of  work  it  is  usual  to  tin  the  prepared  pipe 
ends,  either  with  a  Swedish  torch  or  with  a  soldering  bolt,  and 
to  fix  the  opened  ends  downward.  The  latter  precaution  is 
necessary  to  guard  against  solder  entering  the  barrel  when 
making  the  joints.  To  protect  the  upper  part  of  the  pump 
it  should  be  cased  in,  and  a  suitable  insulating  material  should 
also  be  used  when  a  pump  is  fixed  in  an  exposed  situation. 


314      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


When  a  4-inch  pump  is  used  to  raise  water  through  a  big 
height,  long  handles  are  essential  to  give  the  necessary 
leverage,  but  at  the  same  time  long  levers  limit  the  length  of 
the  stroke  and  are  cumbersome  to  use. 

Double  action  pumps  take  different  forms,  but  when  they 
are  arranged  to  deliver  double  the 
volume  of  water  of  a  single  action 
type  through  a  given  height,  then 
the  power  to  work  them  requires  to 
be  increased.  These  pumps  as  a 
rule  are  operated  by  some  form  of 
motive  power.  The  form  shown  in 
Fig.  208  will  only  raise  the  same 
volume  as  a  single  action  pump, 
but  it  possesses  the  advantage  of 
dividing  the  power  to  raise  the 
water  between  the  upward  and  the 
downward  strokes. 

Lead  pumps,  of  course,  are  not 
suitable  for  raising  water  for  diet- 
etic purposes  if  the  water  has  any 
corrosive  action  on  this  metal,  but 
as  a  rule,  well  waters  contain  tem- 
porary hardness  and  have  no  action 
on  lead. 

Lift  and  Force  Pumps. — Fig. 
209  gives  a  lift  and  force  pump, 
and  this  type  is  commonly  employed 
for  raising  water  to  the  higher  parts 
of  buildings  when  the  water  supply 
is  derived  from  a  well.  The  pump 
is  fixed  to  an  oak  plank,  which  in 
turn  is  secured  to  a  wall  or  other 
structure.  As  already  stated,  when 

a  pump  is  fixed  above  ground  level  the  vertical  distance 
between  it  and  the  water  in  a  well  is  limited  by  atmospheric 
pressure ;  so  far,  however,  as  the  height  to  which  water  above 
the  pump  can  be  raised,  this  is  controlled  by  the  mechanical 
advantage  of  the  lever,  and  the  force  a  person  can  bring  to 


FIG.  209. — Lift  and  force  pump 
by  Nicholls  and  Clarke. 


APPLIANCES    FOR    RAISING    WATER  315 

bear  upon  a  handle  when  working  it  continuously  for  a  given 
time. 

In  a  lift  and  force  pump  the  water  is  put  in  motion  both 
in  the  suction  pipe  P  and  in  the  delivery  pipe  D  with  the 
upward  motion  of  the  bucket ;  the  chief  resistances  to  the 
downward  stroke  are  those  due  to  the  stuffing  box  S,  and  the 
cup-leather  of  the  bucket.  The  guide  G  keeps  the  bucket  rod 
E  in  a  vertical  position,  which  is  essential  when  sliding  through 
a  water-tight  stuffing  box.  The  delivery  D,  like  the  suction 
pipe,  should  not  be  less  than  half  the  diameter  of  the  pump, 
or  the  latter  will  be  difficult  to  work.  Where  a  delivery  pipe 
is  long,  and  where  water  is  raised  through  moderate  heights, 
an  air-vessel  should  be  attached  immediately  above  the  non- 
return valve  n.  An  air-vessel  has  the  effect  of  diminishing 
shock  at  the  commencement  of  the  stroke,  and  of  reducing 
the  power  to  put  the  water  in  the  delivery  pipe  in  motion. 
An  air-vessel  of  a  large  size  should  be  used,  in  order  that  a 
large  portion  of  the  water  at  each  stroke  may  enter  it. 

The  confined  air  in  a  vessel  on  a  delivery  main  acts  like  a 
spring  in  compression,  its  force  per  sq.  inch  being  equal  to  that 
of  the  column  of  water  which  presses  upon  the  air-vessel.  A 
non-return  valve  /*  is  essential  for  a  lift  and  force  pump,  to 
prevent  the  water  in  the  delivery  main  from  exerting  pressure 
on  the  bucket  when  the  latter  is  descending. 

At  T,  Fig.  209,  water  can  be  obtained  directly  from  a 
well,  and  the  tap  also  admits  of  the  delivery  main  being 
emptied. 

In  Fig.  210  a  plunger  or  force  pump  is  given.  With  this 
form  of  pump  the  water  is  displaced  from  the  barrel  with 
the  downward  stroke,  and  the  delivery  pipe  joins  at  the 
bottom  of  the  pump  as  in  the  figure.  So  far  as  the  amount 
of  power  for  working  a  pump  is  concerned,  the  plunger  type 
possesses  an  advantage  over  the  lift  and  force  form,  for  with 
the  former  the  energy  required  is  divided  between  the  upward 
and  the  downward  strokes,  whilst  with  the  latter  practically 
the  whole  of  the  burden  comes  upon  the  upward  stroke. 

The  bucket  of  a  plunger  pump  is  often  formed  with 
double  cup-leathers,  and  the  non-return  valve  and  air-vessel 
may  be  arranged  as  shown.  A  draw-off  cock  should  be 


316      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


provided  just  above  the  non-return  valve,  in  order  that 
the  air-vessel  may  have  its  air  supply  renewed  when 
necessary. 

When  lift  and  force  pumps  are  used  for  raising  water 
from  deep  wells,  double  barrelled  types,  Fig.  211,  are 
frequently  adopted.  When  pumps  have  double  barrels  the 
rods  balance  each  other,  as  one  rod  is  arranged  to  ascend 

whilst  the  other  descends ; 

moreover,  double  barrelled 

pumps  can  be  of  smaller 
DELIVERY  diameter  when  compared 

PIPE.  with  single  forms,  and  the 

power  necessary  to  work 

them    can     be     better 

utilised. 

Pumps  for  deep  wells 

are     generally     provided 
PLUNGER,    with  wheel  and  cranks  in 

lieu    of     levers,    as     the 


as 

former  admit  of  the  better 
utilisation  of  energy  when 
working  them,  and  they 
can  be  operated  from  two 
sides  at  the  same  time  by 
adding  the  extra  handle 
H,  as  in  Fig.  211.  The 
wheel  W  should  be  about 
4  feet  diameter,  and  be  of 
moderate  weight  so  as  to 
serve  the  purpose  of  a  fly- 
wheel. 


5uCTIONJ 

PIPE. 


FIG.  210. — Plunger  type  offeree  pump. 


Double  barrelled  pumps  do  not  require  sucli  large  air- 
vessels  as  single  pumps,  as  the  delivery  of  water  is  more 
nearly  regular.  It  will  be  observed  in  Fig.  211  that  twice 
the  length  of  the  crank  determines  the  length  of  the  stroke, 
and  that  with  an  ungeared  pump  a  stroke  is  completed  at 
each  revolution  of  the  wheel. 

In  some  cases,  where  water  requires  to  be  raised  through 
more  or  less  considerable  height,  and  where  only  hand  power 


APPLIANCES   FOR   RAISING   WATER 


317 


FIG.  211. — Double  barrelled  lift  and  force  pump. 


318      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

is  available,  gearing  is  resorted  to.  The  effect  of  gearing  is  to 
reduce  the  working  power  by  spreading  the  effort  over  a 
longer  period ;  in  other  words,  for  each  complete  stroke  of  a 
pump  the  wheel  will  make  two  or  more  revolutions,  according 
to  the  ratio  of  the  gearing  adopted. 

For  farms  and  other  places,  where  horse  power  is  available, 
that  form  of  energy  may  be  utilised  for  raising  water  by 
providing  suitable  gearing. 

When  it  is  necessary  to  raise  large  volumes  of  water 
through  a  great  height  in  a  limited  time,  some  form  of  motive 
power  becomes  necessary. 

In  country  districts  windmills  or  wind  engines  can  often 
be  utilised  for  raising  large  volumes  of  water  at  a  compara- 
tively small  cost,  but  for  these  appliances  to  be  effective 
they  require  to  be  fixed  in  exposed  situations.  Wind  engines 
are  arranged  to  automatically  adjust  themselves  to  suit  either 
moderate  or  high  velocities  of  wind,  and  also  when  blowing 
from  any  direction. 

The  size  of  a  mill  is  governed  by  the  amount  of  work  to 
be  done,  and  by  its  relative  position  to  surrounding  objects 
which  may  obstruct  the  wind.  For  example,  a  10-foot  mill 
in  an  exposed  situation  may  be  equal  in  power  to  a  16 -foot 
mill  which  is  located  in  a  somewhat  sheltered  position. 
Koughly  speaking  the  power  of  a  wind  engine  varies  according 
to  the  square  of  its  diameter,  when  other  conditions  are  equal. 

It  is  occasionally  found  that  after  a  pump  has  been 
installed  it  gets  more  difficult  to  work,  but  the  cause  as  a 
Kiile  is  not  difficult  to  discover.  For  example,  if  a  lift  and 
force  pump  requires  more  energy  to  work  it  than  it  should 
do,  the  first  thing  that  should  be  done  is  to  ascertain  on 
which  side  the  cause  has  been  introduced.  This  can  be 
readily  done  by  opening  the  draw-off  tap  so  as  to  empty  the 
delivery  main,  when  a  smart  stroke  or  two  will  indicate 
whether  the  bucket  works  too  tightly  in  the  barrel,  or  whether 
the  suction  pipe  is  partially  choked.  Should  the  suction 
side  of  the  pipe  be  found  satisfactory,  then  it  is  obvious  that 
the  fault  is  on  the  delivery  side.  Under  the  latter  circum- 
stances it  is  possible  that  the  air-vessel  has  been  water-logged, 
or  if  this  is  not  the  cause,  then  the  delivery  main  should  be 


APPLIANCES    FOR    RAISING    WATER  319 

examined  to  see  if  it  has  been  flattened  at  any  point;  the 
non-return  valve  at  the  foot  of  the  delivery  pipe  should  also 
receive  attention. 

Centrifugal  Pumps. — The  ordinary  type  of  centrifugal 
pump  is  of  simple  construction,  the  water  being  raised  by 
an  impeller  which  is  keyed  to  a  shaft,  and  which  revolves 
at  a  high  velocity  inside  a  metal  casing.  The  impeller 
usually  contains  six  vanes,  and  the  water  enters  at  the  centre 
and  leaves  at  the  tips  of  the  vanes.  To  utilise  as  far  as 
practicable  the  energy  due  to  the  revolving  mass,  the  space 
into  which  the  water  is  delivered  upon  leaving  the  impeller 
is  gradually  enlarged  towards  the  outlet  of  the  pump.  This 
form  of  construction  has  the  effect  of  reducing  the  velocity  of 
the  water  as  it  approaches  the  outlet,  and  of  converting  its 
kinetic  energy  into  pressure.  This  form  of  centrifugal  pump 
delivers  a  constant  stream,  and  is  very  suitable  for  raising 
large  volumes  of  water  through  a  comparatively  small  height. 
The  efficiency  of  centrifugal  pumps  diminishes  as  the  height 
of  the  lift  is  increased. 

High  Lift  Centrifugal  Pumps. — During  recent  years  great 
improvements  have  been  effected  in  the  construction  of 
centrifugal  pumps,  and  the  limited  heights  to  which  water 
could  be  economically  raised  by  earlier  types  has  been  largely 
overcome  by  constructing  these  pumps  in  compound  form. 

Instead  of  one  chamber,  two  or  more  are  provided,  each 
having  its  own  impeller,  which  is  keyed  to  one  common  shaft. 
After  water  is  delivered  from  the  first  impeller,  it  passes  into 
the  second  chamber,  and  thence  through  the  rising  main  or 
subsequent  chambers. 

Single  impeller  pumps  of  special  design  will  raise  water 
through  a  height  of  over  150  feet. 

Air-Lift  Pumps.  -  -  These  can  only  be  used  for  wells 
which  have  a  considerable  depth  of  water,  and  under  the  best 
conditions  air-lift  pumps  only  have  a  small  mechanical 
efficiency.  For  this  type  of  pump,  air  is  delivered  under  a 
certain  pressure  through  a  nozzle  at  the  botton  of  the  rising 
main,  the  lower  end  of  which  must  be  submerged  to  a  greater 
depth  than  the  height  through  which  water  is  to  be  raised. 
An  air  compressing  plant  is  essential  to  operate  these  pumps, 


320      DOMESTIC   SANITARY   ENGINEERING    AND    PLUMBING 

and  when  sufficient  air  at  the  necessary  pressure  is  delivered 
through  the  submerged  nozzle,  the  downward  pressure  of  the 
water  in  the  well  is  sufficient  to  overcome  that  of  the  air  and 
water  in  the  rising  main,  when  water  is  caused  to  rise  and 
escape  at  the  outlet.  The  air  and  water  do  not  mix,  but 
form  themselves  into  alternate  bands  or  short  columns  in  the 
rising  main. 

Efficiency  of  Pumps.  —  If  a  pump  were  perfect  it  would 
raise  in  a  given  time  a  volume  of  water  equal  to  the  space 
traversed  by  the  plunger,  multiplied  by  the  number  of  strokes 
in  the  time  under  consideration.  In  practice  less  water  than 
the  above  would  be  raised  on  account  of  a  certain  volume 
slipping  back  during  the  closing  of  the  valves  and  by  leakage 
at  the  sides  of  a  bucket.  If  a  pump  is  in  good  condition  it 
may  have  an  efficiency  as  high  as  99  per  cent.,  and  on  the 
other  hand  its  efficiency  may  fall  to,  or  below,  50  per  cent. 
when  in  a  poor  or  indifferent  state  of  repair.  Lever  pumps  as 
a  rule  are  not  so  efficient  as  wheel  pumps,  as  the  latter  have 
a  more  nearly  uniform  stroke,  whilst  the  former  are  more 
jerky  in  action  and  are  not  always  given  a  complete  stroke. 

For  the  purpose  of  calculation  lever  pumps  will  be 
assumed  to  have  an  efficiency  of  85  per  cent.  This  is  a  fair 
basis  to  work  upon,  and  a  standard  which  any  good  form  of 
pump  should  satisfy  when  not  worked  exactly  under  ideal 
conditions. 

Lever  Pump  Formula.  —  The  lifting  capacity  of  an 
ordinary  lever  pump  upon  the  basis  stated  can  be  obtained 
by  the  following  formula  :  — 


416 

Where  G  =  volume  of  water  raised  in  gallons. 

I  =  length  of  stroke  in  inches. 
„         d  =  diameter  of  pump  in  inches. 
„         n  =  number  of  strokes  per  minute. 
„          t  =  time  of  pumping  in  minutes. 
Example  11.  —  An  ordinary  lift  pump  is  3J  inches  diameter, 
how  many  gallons  of  water  would  it  raise  in  half  an  hour  with  a 
9  -inch  stroke,  and  when  worked  at  20  strokes  per  minute  ? 


APPLIANCES    FOR   RAISING    WATER  321 


By  Formula  27,  G 

(3  J)2x  9x20x30     33075 
Substituting  values,  G  =  -^  g          -  =  , 

.'.  G  =  159  gallons,  which  are  raised  in  half  an  hour. 

Assuming  the  diameter  of  a  lever  pump  is  required  for  raising 
a  given  volume  of  water  in  a  certain  time.  By  transposing 
Formula  27  we  have — 

d=     /GX416  (28) 

v  Ixnxt 

Example  12. — Determine  the  diameter  of  a  lever  pump 
which  will  raise  65  gallons  in  20  minutes,  if  it  has  a 
7-inch  stroke  and  when  worked  at  the  rate  of  22  strokes 
per  minute. 

Formula  28  gives  d  =  \/Gx416. 
Ixnxt 


Substituting  the  values  given,  d  = 


7  X  *2t2i  X 


.*.  d  =  2'96,  or  say  3  inches  diameter. 

The  power  which  is  necessary  for  operating  a  lever  handled 
pump  can  be  obtained,  when  the  length  of  each  part  of  the 
lever  from  the  fulcrum,  and  the  resistances  to  be  overcome,  are 
known.  In  Fig.  212  an  ordinary  pump  handle  is  shown  which 
represeats  a  lever  of  the  first  order. 

By  the  following  general  formulae  any  one  of  the  four 
values  which  are  represented  by  the  symbols  can  be  found 
when  the  other  three  are  given.  In  pump  calculations  the 
actual  weight  of  a  handle  is  not  taken  into  account,  as  the 
bucket  nullifies  to  a  great  extent  the  advantage  derived  by  the 
extra  weight  of  the  longer  arm. 

(29) 
.  ,     (30) 

21 


322      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


(31) 
(32) 


Where  P  =  the  resistance  to  be  overcome  when  pumping. 
„        y  =  length  of  short  side  of  lever  in  inches. 
„        x  =  length  of  long  side  of  lever  in  inches  (length  to 

centre  of  grip,  as  in  Fig.  212). 
„       F  =  force  or  effort  applied  near  end  of  lever. 
,  Example  13. — Suppose  the  resist- 

4»  ance  to  be  overcome  in  pumping  is 

equal  to  80  lb.,  and  the  lengths  of 
the  short  and  long  side  of  lever  are 
6  inches  and  30  inches  respectively, 
what  force  should  be  exerted  on  the 
end  of  the  lever  ? 

In  Formula  3 1,  F  = 


and    upon 
given, 


substituting   the    values 


80_x_6. 
30     ' 

/.  F  =  161b. 

With  a  force  of  16  lb.  on  the  long 
end  of  lever  the  latter  would  be  in  a 
state  of  equilibrium,  assuming  that 
its  weight  need  not  be  taken  into 
account. 

In  order  to  make  the  latter  form- 
ulae applicable  to  pump  work,  it  is 
necessary  to  ascertain  the  value  of  P. 
The  actual  resistances  to  be  overcome 
when  pumping  vary  with  the  different 
types  of  pumps.  In  lift-and-force 

pumps  frictional  resistances  are  greater  than  those  of  ordinary 
lift  pumps,  and  lift-and-force  pumps  when  geared  offer  still 
greater  resistance  by  friction. 

Formulas    for  Lift    Pumps. — The    total   resistance    to  be 


FIG.  212.— Sketch  illustrat- 
ing mechanical  advantage 
of  lever. 


APPLIANCES   FOR   RAISING   WATER  323 

overcome   when    raising   water   by  an    ordinary  lift    pump 
Fig.  206,  may  be  obtained  by  the  following  formula  :  — 


^  /Qo\ 

-IB"  (33) 

Where  P  =  total  resistance  in  Ibs.  to  be  overcome. 

„        d  =  diameter  of  pump  in  inches. 

„        h  =  height  in  feet  through  which  water  is  raised. 
When  the  right  side  of  the  equation  in  33  takes  the  place 
of  P  in  Formulae  31  and  32,  we  obtain  the  following  :  — 


•  '         '     (34) 


and  by  transposition,  d  =  ^  .         .        .         .    (36) 

When  an  ordinary  lift  pump  is  used  for  raising  water  for 
supplying  a  house,  its  diameter  as  a  rule  does  not  exceed  4 
inches.  Where  the  short  and  long  parts  of  a  lever  are  in  the 
ratio  of  1  to  6  a  4-inch  pump  should  not  be  difficult  to  work. 

Example  14.  —  If  a  4-inch  lift  pump  raises  water  through 
a  height  of  24  feet,  and  the  short  and  long  sides  of  lever 
are  6  inches  and  36  inches  respectively,  determine  the  effort 
which  must  be  applied  at  the  end  of  the  lever. 

-D    T?         i    OA  ^ 
By  Formula  34,  F  = 


„    42x9x24x6     576 
Substituting  values  given,  1  =  —  ^5x3Q  —  =  "25  ' 

/.  F  =  23  gV,  or  say  23  lb.,  which  must  be  applied  at  the  end 
of  the  lever. 

The  effort  that  can  be  applied  by  a  person  is  limited,  and 
as  a  rule  this  will  vary  from  18  to  25  lb.  when  pumping 
continuously  for  fairly  long  periods.  The  length  of  a  pump 
handle  is  also  limited,  for  when  a  handle  is  very  long  it  cannot 
be  raised  sufficiently  high  to  utilise  the  full  length  of  its 
stroke.  It  is  also  cumbersome  to  work. 

The  diagram  Fig.  213  shows  the  distances  through  which 


324      DOMESTIC   SANITARY    ENGINEERING    AND   PLUMBING 

the  hand  travels  with  handles  of  varying  lengths  when  the 
levers  are  moved  through  90°.  The  vertical  distances 
through  which  the  hand  is  raised  are  also  given.  With 
a  handle  2  feet  long  it  will  be  seen  that  the  distance  through 
which  the  hand  travels  is  3  ft.  If  in.,  whilst  the  vertical 
height  is  2  ft.  3  in.  For  a  4-foot  handle  the  length  of  the 


J!  » 


/ 

/ 

'        /' 

;i 

/ 

/i      /i       , 

i 

/ 

/i      /i      / 
/  '     «  i     / 

1     / 

Vvx/       -^ 

/"*!    /    ,     / 

/ 
/ 
/ 

V' 

7  y  ^v7  >= 

/;             i/        -' 

/I                     /                CO 

/I               /  ' 

/ 
/ 
/ 
/ 
/ 

^'"               jff 

'            /'         J 

>x        /  ' 

& 
i 

1    /      1       / 

—  -  "^"  "*"                                                            X" 

1    x              ,         / 

f               x 

^' 

^J              1    x 

^"^                      $ 

V  x                       ^x' 

/  i 

___-'*"" 

i 

^~-~" 

1 

FIG.  213. — Diagram  illustrating  limiting  lengths  for  pump  handles. 

arc  and  the  vertical  distance  are  6  ft.  3f  in.  and  4  ft.  5J  in. 
respectively.  In  Fig.  213  the  short  lever  arm  is  6  inches, 
and  when  this  is  turned  through  90°  it  gives  a  stroke  of 
8J  inches.  Should  the  length  y  be  less  than  6  inches  the 
stroke  would  be  shorter  than  shown,  unless  the  handle  were 
moved  through  a  greater  number  of  degrees. 

Formulae  for  Lift-and-Forqe  Pumps. — To  find  the  diameter 


APPLIANCES   FOR    RAISING    WATER  325 

of  a  lift-and-force  pump  for  raising  water  through  more  or 
less  considerable  height,  and  where  the  power  and  leverage 
are  limited,  the  following  formula  can  be  used  : — 

50x#xF 


Where  d  —  diameter  of  pump  in  inches. 
„      x  =  long  side  of  lever  in  inches. 
„     y  =  short  side  of  lever  in  inches. 
„     F  =  force  applied  on  pump  handle. 
„     h  =  height  through  which  water  is  raised. 
Example  15.  —  Determine  the  diameter  of  a  lift-and-force 
pump  for  raising  water  through  a  total  height  of  75  feet, 
when   the  short  and   long  parts   of  lever  are  5  inches  and 
33  inches  in  length,  and   when   a  force  of   24  Ib.   is  to   be 
applied  at  the  end  of  the  lever. 


/ 
By  Formula  37,  ^  =  V 


50x#xF 
9xTx? 


_ 

Substituting  values  given,  d  =     /5Qx  33x24 

^    19x75x5 
/.  ^  =  2*35  inches  diameter. 

As  this   is  an  odd   size  the   nearest  stock  size  would  be 
selected. 

Transposing  Formula  37,  we  have  — 


(38) 
50  xx 

Example  16.  —  Supposing  a  lift-and-force  pump,  Fig.  209,  is 
of  3  inches  diameter,  and  is  used  for  raising  water  through  a 
height  of  60  feet;  what  force  must  be  exerted  on  the  end 
of  the  lever  when  the  short  and  long  sides  are  5  inches  and 
32  inches  respectively  ? 

By  Formula  38,  F  =  ^^A2iy- 

OU  X  X 

a  ,    ...   ..  ,,     32x  19x60x5      513 

Substituting  values  given,  1  =  --  50^32  --  =  l6~  ' 

/.  F  =  32Ty,  say  32  Ib. 

Example  17.  —  Give  the  volume  of  water  which  would  be 
raised  by  the  pump  in  the  last  example  in  fifteen  minutes,  if  it 


326      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


has  a  7 -inch  stroke  and  is  worked  at  the  rate  of  22  strokes 
per  minute. 


By  Formula  27,  G  = 
Substituting  values  given,  G  = 


d^xlxnxt 


416 
32x7x22xl5     10395 


416  208   ' 

=  49*9,  or  say  50  gallons. 

Wheel-pumps  have 
an  advantage  over  those 
with  lever  handles,  as 
the  former  give  a  full 
stroke  with  each  revolu- 
tion of  the  crank  they 
better  utilise  the  energy 
imparted  to  them,  and 
are  less  jerky  in  action. 
By  the  aid  of  Fig. 
214  the  mechanical  ad- 
vantage of  a  wheel  will 
be  made  clear,  besides 
helping  to  explain  the 
meaning  of  the  symbols 
used. 

Formula  for  Single 
Action  Lift  -  and  -  Force 
Wheel  Pumps. — For  lift- 

and-force  pumps  like  Fig.  211,  and  where  the  rods  are  balanced, 

the  following  formula  may  be  used : — 


•    (39) 
(40) 


FIG.  214. — Illustrating  mechanical  advantage 
of  wheel  handle. 


50xE 

/Fx50xE 
d=\J    igxh/xr  • 

Where  F  =  force  in  Ibs.  applied  to  handle  of  wheel. 
„       r  =  radius  of  crank  in  inches. 
„      E  =  radius  of  wheel  as  in  Fig.  214. 
„       d  =  diameter  of  pumps  in  inches. 
„      h  =  height  through  which  water  is  raised. 


APPLIANCES   FOR   RAISING   WATER 


327 


It  will  be  observed,  upon  reference  to  Fig.  214,  that  the 
length  of  the  crank  r  determines  the  length  of  the  stroke, 
which  is  equal  to  twice  that  of  the  crank.  For  convenience 
the  radius  E  of  pump  wheel  is  often  limited  to  14  or  15 
inches,  but  where  the  resistances  to  be  overcome  are  large  a 
bigger  radius  may  be  adopted,  or  gearing  may  be  resorted  to. 

The  usual  form  of  gearing  is  shown  in  Fig.  215,  where  the 


FIG.  215. — Gearing  for  double  barrelled  deep  well  pump. 

pump  wheel  is  connected  to  a  shaft  on  which  are  small  cog 
wheels,  which  in  turn  react  on  larger  cog  wheels  to  which 
the  crank  rod  is  joined.  The  ratio  of  the  gearing  is  obtained 
by  counting  the  number  of  cogs  in  each  wheel.  Thus,  if  the 
upper  and  smaller  wheel  contains  6  cogs,  and  the  larger  or 
lower  wheel  15  cogs,  then  the  gearing  is  in  the  ratio  of  15  to 
6,  or  2  J  to  1 ;  in  other  words,  2J  revolutions  of  the  fly  wheel 
are  necessary  to  complete  one  stroke  of  the  pump.  For 
purposes  of  calculation  the  higher  number  will  be  expressed 


328      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


as   a  ratio   of  the  smaller,  and  for  the  case  referred  to  this 
ls  ^7. 

Z2 

Formulae  for  Geared  Lift-and-Force  Pumps.  — 


equals    7. 


,        .  .     (42) 


Where  £  =  the  ratio  of  the  revolutions  made  by  the  wheel 
to  one  made  by  the  crank. 

The  remainder  of  the  notation  as  before. 

Example  18.  —  Find  the  force  which  must  be  applied  to  the 
handle  of  a  3-inch  diameter  lift-and-force  wheel-pump,  in 
order  to  raise  water  through  a  height  of  120  feet,  when  the 
radii  of  the  crank  and  wheel  handle  are  4J  and  18  inches 
respectively. 

As  the  pump  in  the  example  is  not  geared,  the  force  to 
work  it  will  be  found  by  Formula  39. 

Where  F  = 


^  —  „  --  . 
50  xK 

Q  ,,.,,.          ,         .         „     32xl9xl20x4J    513 

Substituting  values  given,  F  =  -    —  ^  —  ^  --  =  -=-  ; 

OU  X  -Lo  0 

.-.  F=102f  Ib. 

The  working  shows  that  the  pump  is  unsuited  for  manual 
labour  where  only  one  or  two  persons  could  operate  it.  If  it 
is  assumed  that  two  men  could  be  employed  to  work  the 
pump,  each  would  require  to  exert  about  51  Ib.  on  the  wheel 
handle. 

Example  19.  —  Suppose,  now,  we  desire  to  find  the  diameter 
of  a  pump  which  can  be  worked  by  one  man  when  exerting 
a  force  of  28  Ib.  on  the  wheel  handle,  in  order  to  raise  water 
through  a  height  of  120  feet.  Assume  the  wheel  is  geared 
in  the  ratio  of  3  to  1,  and  that  the  radii  of  the  crank  and  the 
wheel  are  4J  inches  and  18  inches  as  before. 


By  Formula  42,  d= 


Xhxqxr 


APPLIANCES   FOR    RAISING   WATER  329 


c  ,,.,,..,         ,          .          ,         /     28  x  5  x  18  ,- 

Substituting  the  values  given,  ^  =  V  2  x  120x£x4£=     '  ' 

/.  d=2'64,  or  say  2|  inches  diameter. 

Should  the  lifting  capacity  of  a  geared  wheel-pump  be 
required,  it  may  be  directly  obtained  by  the  following  :  — 


_ 

190 

Where  G  =  gallons  raised. 

„       d  —  diameter  of  pump  in  inches. 

„       r  =  radius  of  crank  in  inches. 

„      n  =  number  of  revolutions  made  by  fly  wheel  per 

minute. 

„       t  =  time  in  minutes. 
„       q  =  the  ratio  of  gearing  adopted. 
„      B  =  number  of  pump  barrels. 

Example  20.  —  Find  the  volume  of  water  which  should  be 
raised  in  35  minutes  by  a  double-barrelled  lift-and-force 
pump  of  2  inches  diameter,  where  the  fly  wheel  makes 
30  revolutions  per  minute  and  where  the  crank  has  a  radius 
of  4J  inches.  The  wheel  is  also  geared  in  the  ratio  of  2J  to  1. 

By  Formula  43,  G  =  *xrx*x*xgxB. 

j.y  \j 

Substituting  the  values  given, 


190  19    : 

,  or  say  80  gallons. 

Hydraulic  Rams.  —  Where  sufficient  water  is  available  for 
working  hydraulic  rams,  they  are  very  suitable  for  auto- 
matically raising  water  for  supplying  mansions,  farms,  hotels, 
hamlets,  etc.  These  appliances  may  be  divided  into  two 
classes,  viz.,  those  which  raise  a  portion  of  the  water  which 
operates  them,  and  those  which  utilise  the  energy  from  one 
source  in  order  to  raise  water  from  a  separate  source.  The 
latter  are  occasionally  termed  ram-pumps.  Each  class  of 
ram  varies  widely  in  constructional  details,  but  when  well 


330      DOMESTIC   SANITARY   ENGINEERING   AND   PLUMBING 

constructed  rams  will  work  with  a  very  small  head  of  water. 
A  head  of  18  inches  and  a  little  less  is  sufficient  to  operate 
certain  rams  of  the  first  class,  provided  they  are  properly  fixed. 
For  every  foot  of  working  head,  water  may  be  raised  by  a  ram 
through  a  height  of  over  50  feet,  but  the  efficiency  of  this 
appliance  rapidly  falls  when  only  small  heads  are  used  to 
force  water  to  high  elevations. 


FIG.  216. — Walter  Simpson's  hydraulic  ram. 

A  section  of  a  ram  by  Walter  Simpson,  Aberdeen,  is  given 
in  Fig.  216,  the  inlet  being  at  I  and  the  outlet  at  0.  The 
ram  contains  two  valves,  the  larger  one  D  being  known  as 
the  dash  valve,  and  the  smaller  one  V  acts  as  a  non-return 
valve.  It  will  be  observed  that  the  dash  valve  is  closed  with 
an  upward  motion,  whilst  the  non-return  valve  opens  in  the 
direction  of  the  flow. 

For  its  action,  the  ram  depends  upon  the  velocity  of 
the  inflowing  water  being  suddenly  arrested  by  the  closing 


APPLIANCES   FOR    RAISING    WATER 


331 


of  the  dash  valve  D, 
when  the  pressure  in- 
side the  ram  is  suddenly 
raised.     At  the  period 
of  maximum  pressure  a 
small  volume  of  water 
is  forced  through   the  valve   V   into   the 
air-vessel,  from  which  it  passes  through  the 
outlet  0  into  the  rising  main.     Although 
water  escapes  into  the  air-vessel,  the  resist- 
ance to  its  entrance  is  sufficient  to  cause 
the  water  in  the  supply  pipe  to  recoil  when 
the  dash  valve  opens  by  its  own  weight. 
As  soon  as  the  energy  which  produces  the 
recoil   or  backward   motion  has  been  ex- 
pended, the  water  in  the  supply  pipe  again 
regains  its  forward  flow,  and  after  a  brief 
interval,   during   which  a  certain   volume 
escapes  through  the  open  dash  valve,  the 
latter  is  again   suddenly   closed  and   the 
operations  repeated. 

In  Fig.  217  a  ram  is  shown  in  position, 
together  with  the  drive  and  delivery  pipes. 
This  illustration  will  also  aid  in  making 
clear  some  of  the  points  which  require 
consideration  in  ram  work.  For  the  suc- 
cessful working  of  a  ram,  the  drive  pipe 
plays  a  very  important  part;  if  this  pipe 
is  too  short,  the  dash  valve  beats  too 
rapidly,  and  the  ram  will  not  do  effective 
duty,  owing  to  insufficient  resistance  being 
offered  to  the  recoil  of  water  when  the  dash 
valve  is  closed.  To  make  the  point  clear 
we  will  assume  that  the  length  of  drive 
pipe  to  a  ram  is,  say,  15  feet;  and  that  the 
working  head  is  *10  feet,  which  is  repre- 
sented by  H  in  Fig.  217;  let  the  height 
through  which  water  requires  to  be  raised 
be,  say,  100  feet.  Under  these  conditions 


332      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

the  working  head  is  10  feet  and  the  resistance  to  be  over- 
come is  that  due  to  a  head  of  100  feet.  Now,  in  order  for 
the  ram  to  raise  water,  the  pressure  inside  it  when  the  dash 
valve  is  closed  will  require  to  exceed  that  due  to  the  head 
on  the  delivery  side.  When  a  ram  is  working,  two  forces 
operate  to  relieve  the  increased  pressure  which  is  due  to  the 
sudden  closing  of  the  dash  valve;  one  is  the  water  which 
escapes  through  the  retaining  valve  and  into  the  air-vessel, 
and  the  other  is  the  recoiling  water  in  the  drive  pipe.  If,  now, 
the  resistance  offered  to  the  recoil  of  water  is  less  than  that 
due  to  the  opening  of  the  retaining  valve,  the  dash  valve  will 
beat,  and  the  ram  will  appear  to  be  working,  when  in  reality 
no  water  is  being  raised.  In  the  case  under  consideration, 
where  the  length  of  the  drive  pipe  is  only  15  feet,  the  resistance 
offered  to  the  recoil  would  be  insufficient,  and  in  consequence 
the  increased  pressure  would  be  principally  relieved  by  the 
drive  pipe,  and  the  recoil  would  occur  at  a  quicker  rate. 

For  reasons  stated  it  becomes  obvious  that  a  long  drive 
pipe  is  essential,  and  as  a  general  rule  it  should  not  be  less 
in  length  than  the  height  through  which  water  requires  to  be 
raised.  Long  drive  pipes  require  to  be  of  adequate  size, 
otherwise  the  dash  valve  will  not  close  quickly  enough. 
When  the  recoil  in  a  drive  pipe  takes  place,  the  water  is 
affected  through  the  whole  of  its  length,  so  the  longer  the 
pipe  the  greater  the  internal  resistances,'  and  the  longer  the 
interval  between  the  beats  of  the  ram. 

When  laying  a  supply  or  drive  pipe,  it  should  have  a 
gradual  rise  from  the  ram  to  the  source  of  supply  as  in 
Fig.  217,  and  where  bends  are  necessary  they  should  be  made 
as  easy  as  practicable.  A  rose,  or  strainer,  should  be  provided 
at  the  inlet  end  of  the  drive  pipe,  to  prevent  any  matter 
passing  into  it  and  so  interfering  with  the  working  of  the  ram. 

Either  iron  or  lead  drive  pipes  may  be  used  according  to 
the  size  required,  but  when  cast-iron  spigot  and  socket  pipes 
are  adopted  the  joints  should  be  made  with  rust  cement. 
Lead  is  not  a  suitable  jointing  material  in  this  case,  as  the 
joints  require  to  be  made  with  a  material  which  imparts  a 
greater  degree  of  rigidity.  Yielding  joints  on  a  drive  pipe 
impair  the  efficiency  of  a  ram. 


APPLIANCES    FOR    RAISING    WATER  333 

When  rams  have  a  high  working  head  they  are  subjected 
to  considerable  strain,  and  as  a  rule  it  should  not  exceed 
30  feet. 

Where  possible  the  supply  of  water  to  a  ram  should  be 
sufficient  to  maintain  a  constant  head  upon  it,  or,  in  other 
words,  the  supply  tank  T,  Fig.  217,  should  be  always  full. 
When,  however,  a  ram  is  supplied  by  a  spring  or  stream  which 
has  a  varying  yield,  a  much  larger  supply  tank  will  be  neces- 
sary than  where  a  large  and  fairly  constant  volume  of  water 
is  available.  Should  a  supply  tank  become  emptied  by  the 
outflow  exceeding  the  rate  of  inflow,  the  ram  will  cease  to 
work,  and  the  water  available  will  flow  through  the  open 
dash  valve  and  thence  to  waste.  To  obviate  this  waste  of 
water  a  float  valve  may  be  attached  to  the  end  of  the  drive 
pipe  in  the  supply  tank,  in  order  to  automatically  shut  off 
the  supply  to  the  ram  when  the  water  level  has  been 
lowered  to  a  certain  point.  During  the  refilling  of  the 
tank  the  float  valve  opens,  and  the  ram  can  then  be 
restarted  by  holding  down  the  dash  valve  for  a  few  seconds, 
or  by  means  of  a  pumping  valve  at  the  supply  tank.  The 
reason  why  the  ram  does  not  restart  itself  is  due  to  the 
gradual  closing  of  the  dash  valve  when  the  supply  is  being 
cut  off. 

Air-vessels  for  rams  should  be  of  a  large  size,  in  order 
that  water  at  each  beat  may  be  first  directly  discharged  into 
them,  without  much  compression  of  the  contained  air.  Rams 
occasionally  fail  to  raise  water  owing  to  air-vessels  getting 
water-logged;  the  beating  of  the  dash  valves  may  continue, 
but  the  resistance  on  the  delivery  side  is  too  great  when  it  is 
necessary  to  first  put  the  water  in  the  rising  main  in  motion. 
When  a  ram  is  in  constant  use  the  air-vessel  should  be  re- 
charged with  air  at  regular  intervals  of,  say,  once  a  week. 
In  a  ram  the  water  is  under  more  or  less  considerable  pressure 
when  it  enters  the  air-vessel,  and  therefore  the  capacity  of 
water  for  the  absorption  of  air  is  increased,  and,  owing  to  the 
water  in  the  air-vessel  being  continually  changed,  the  latter, 
in  consequence,  is  gradually  deprived  of  air. 

To  renew  the  air,  one  or  two  cocks  are  provided  at  the 
base  of  an  air-vessel,  and  when  these  are  opened  and  the 


334      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

valves  on  the  drive  and  delivery  pipes  are  closed,  the  vessel 
is  readily  charged  with  air.  In  many  rams  a  small  air  or 
sniffle  valve  is  provided  for  making  good  a  portion  of  the  air, 
but  it  cannot  be  entirely  relied  upon  for  automatically  supply- 
ing the  requisite  volume,  although  it  will  lengthen  the  interval 
between  the  periods  of  recharging  as  above  described.  An 
air  or  sniffle  valve  opens  and  admits  air  during  the  recoil  of 
the  drive  water,  and  it  is  forced  along  with  water  into  the 
air-vessel  at  each  beat  of  the  ram. 

The  principal  causes  for  rams  getting  out  of  order  are 
due  to  faulty  dash  or  retaining  valves,  to  air-vessels  getting 
water-logged,  to  defects  in  the  pipes,  to  air  in  the  drive  pipe, 
and  to  an  insufficient  supply  of  water. 

Within  certain  limits  a  ram  can  be  made  to  use  less  water 
by  shortening  the  stroke  of  the  dash  valve  by  adding  one 
or  more  washers  at  K,  Fig.  216,  but  the  volume  of  water 
raised  is  also  diminished,  and  the  pulsations  of  the  ram 
are  made  at  a  quicker  rate.  If  a  ram  has  never  given 
satisfaction,  this  may  be  due  to  structural  defects,  or  to  the 
drive  pipe  being  irregularly  laid  so  as  to  permit  of  the 
lodgment  of*  air,  or  to  the  drive  pipe  being  too  small,  or  to 
insufficient  length.  The  leakage  of  a  non-return  valve,  or 
the  lodgment  of  air  in  a  drive  pipe,  causes  the  dash  valve  to 
remain  closed.  A  defect  in  the  lower  part  of  a  delivery  pipe 
would  also  have  a  similar  effect.  Water-logged  air-vessels, 
and  drive  pipes  which  are  too  short,  allow  pulsations  to 
continue  without  raising  water. 

When  a  ram  is  newly  started,  the  water  will,  of  course, 
rise  in  the  delivery  pipe  to  the  same  level  as  that  in  the 
supply  tank.  At  this  period,  provided  there  is  an  ample 
supply  of  water,  the  dash  valve  will  be  closed,  and  in  order 
to  start  the  ram  it  will  be  necessary  to  open  the  dash 
valve  several  times,  by  hand,  until  water  is  forced  through 
the  delivery  pipe  to  a  height  which  offers  sufficient  resist- 
ance, to  bring  about  the  recoil  of  the  water  in  the  drive 
pipe. 

With  regard  to  the  volume  of  water  a  ram  will  raise,  this 
can  be  calculated  when  its  efficiency  for  the  given  conditions 
is  known.  When  a  certain  volume  of  water  flows  through  a 


APPLIANCES   FOR    RAISING    WATER  335 

drive  pipe,  its  energy  is  usually  calculated  in  foot-pounds. 
This  is  obtained  by  multiplying  the  weight  of  water  by  the 
height  through  which  it  falls.  For  example,  if  the  working 
head  on  a  rani  is  10  feet,  and  100  Ib.  of  water  are  delivered 
to  it  per  minute,  the  energy  in  the  drive  water  for  the  time 
given  is  equal  to  100x10  =  1000  ft.-lb.  Assuming  that 
10  Ib.  of  water  are  raised  in  the  same  interval  of  time 
through  a  height  of  90  feet,  then  the  energy  to  raise  this 
volume  through  the  height  given,  when  frictional  resistances 
are  neglected,  is  equal  to  10x90  =  900  ft.-lb.  But  as  the 
drive  water  contains  1000  ft.-lb.  of  energy,  then  (1000-900) 
=  100  ft.-lb.  which  are  absorbed  by  friction  and  by  leakage, 
etc.  Under  these  circumstances  the  efficiency  of  the  ram 

.,  ,     900x100     ftA 
would  be  —  JQQQ  —  =  90  per  cent. 

Of  the  100  Ib.  of  water  which  are  delivered  to  the  ram 
only  10  Ib.  are  raised,  the  remaining  90  Ib.  escape  through 
the  dash  valve  and  flow  away  to  waste. 

For  making  calculations  in  connection  with  rams  the 
following  formulae  may  be  used  :  — 

GxHxe 

r~  -JT-;     •     '.     '     •     •     •  (44) 

G-*  :.-        -        .        -        -         -     (45) 


Where  G  =  gallons  supplied  to  ram  in  any  given  time. 

„       q  =  gallons    raised    during    the    same    interval    of 

time. 

„      H=  head  of  water  upon  ram. 
„      h  =  height  through  which  water  is  raised. 
„       e  =  efficiency  of  ram. 

In  Fig.  217  H  and  h  are  indicated.  Only  approximate 
values  of  e  can  be  given,  as  these  vary  with  different 
ratios  of  H  and  h,  and  with  different  makes  of  rams.  The 
efficiency  of  a  ram  is  also  influenced  by  the  manner  in  which 
it  is  fixed. 


336      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


TABLE  VI 

VALUES  OF  e 

Where  g  = 

2 

3 

4 

5 

6 

9 

12         15 

20 

e  = 

•88 

•85 

•81 

•75 

•72 

•63 

•5          -4 

•3 

! 

Example  21. — A  ram  when  working  with  a  full  beat 
requires  a  supply  of  12  gallons  per  minute.  Assuming  the 
ram  has  an  efficiency  of  85  per  cent,  when  raising  water 
through  a  height  of  120  feet,  and  when  the  working  head  is 
19  feet,  how  many  gallons  should  it  raise  per  hour  ? 
Supply  per  hour  =  12  x  60  =  720  gallons. 

,  GxHxe 

By  Formula  44,  q  — 


Substituting  values,  q  = 


h 

720  x  19  x '85 
120 


.-.  2  =  96'9,  or  say  97  gallons  per  hour. 

Example  22.  —  In  24  hours  a  ram  delivers  140  gallons 
through  a  height  of  160  feet.  If  the  working  head  is  15  feet, 
efficiency  of  ram  64  per  cent.,  determine  the  rate  of  supply 
per  minute  the  ram  will  require. 

The  volume  of  water  raised  per  minute 


Using  Formula  45,  G  = 


n     160  x  -097 
Substituting  values  given,  G  =  -y=  —  ^—  ; 

/.  G  =  1'6  gallons  per  minute  as  the  volume  required. 
Example  23.  —  Find  the  efficiency  of  a  ram  which  raises  950 
gallons  per  day  through  a  height  of  75  feet,  when  the  rate  of 
supply  is  18,000  gallons  per  day  and  when  the  working  head  is 
7  feet. 

By  Formula  46,  *= 


Substituting  values  given,  e  = 


GxIT 

75x950 


18000x7 
/.  e  =  '565,  or 


per  cent. 


APPLIANCES   FOR   RAISING   WATER 


337 


The  following  table  gives  approximate  sizes  of  drive  and 
delivery  pipes  for  rams : — 


TABLE  VII 


Water  delivered  to  ram 
per  minute. 

Diameter  of  drive 
pipe. 

Diameter  of 
delivery  pipe. 

1  to    3  gallons. 

1    inch. 

£  inch. 

3 

8 

1^ 

1 

8 

16 

2 

16 

24 

2i 

11 

24 

32 

3 

li 

32 

50 

3i 

]i 

50 

60 

4 

2 

A  hydraulic  ram  of  the  second  type,  by  Keiths,  Blackman 
&  Co.  Ltd.,  is  shown  in  Fig.  218.  With  this  appliance,  a  pure 
and  limited  supply  of  water  can  be  raised  by  means  of  impure 
water,  when  the  latter  is  obtainable  in  sufficient  volume.  The 
two  waters  are  not  able  to  mix,  as  each  is  supplied  to  separate 
parts  of  the  appliance,  and  any  leakage  at  the  pistons  is  free 
to  escape  to  the  exterior  of  the  ram.  From  the  figure  it  will 
be  observed  that  the  lower  part  resembles  an  ordinary  ram, 
whilst  the  upper  part  resembles  a  single  action  pump. 

Where  practicable,  the  pure  water  should  flow  by  gravity 
to  the  appliance,  but  "if  this  is  not  possible,  then  it  may  be 
raised  a  few  feet  through  a  suction  pipe.  The  action  of  the 
ram  pump  shown  is  as  follows,  where  the  pure  water  will 
flow  by  gravitation  to  the  ram.  When  the  piston  K  is  in 
the  position  shown,  water  flows  through  the  non-return  valve 
V1,  and  fills  the  cylinder  C.  The  impure  water  which  supplies 
the  motive  power  enters  at  A,  and  when  the  dash  valve  D  is 
rapidly  closed,  the  energy  due  to  concussion  is  exerted  on  the 
piston  Pp  which  is  directly  joined  by  means  of  rod  K  to  the 
upper  piston  P2.  With  each  beat  of  the  dash  valve,  the  pistons 
are  caused  to  rise,  and  to  displace  the  pure  water  from 
cylinder  C,  through  the  retaining  valve  V2  and  into  the  air- 
vessel  ;  from  the  latter,  the  water  flows  through  the  delivery 
pipe  to  the  point  desired.  During  the  recoil  of  the  water  in 


22 


338      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


PURE  WATER^  i 
SUPPLY  PIPE.  * 


OUTLET 


FIG.  213. — Keith  and  Blackman's  hydraulic  ram  pump. 


APPLIANCES    FOR    RAISING   WATER  339 

the  drive  pipe  the  dash  valve  opens,  the  pistons  descend,  and 
the  cylinder  C  receives  a  fresh  charge  of  pure  water.  These 
operations  are  repeated  so  long  as  the  ram  continues  to  work 
satisfactorily.  To  aid  the  downward  motion  of  the  pistons, 
a  weighted  lever  operates  on  the  rod  at  W.  It  is  now  clear 
why  pure  water  should  flow  by  gravity  to  the  ram,  for  as  it 
requires  to  be  raised  by  the  downward  motion  of  the  pistons, 
the  power  available  is  only  that  obtained  by  means  of  the 
weighted  lever. 


CHAPTEK  XII 
HYDROSTATICS  AND  HYDRAULICS 

Hydrostatics  is  that  branch  of  science  which  treats  upon 
the  equilibrium  of  fluids.  In  this  case  it  is  confined  to  the 
pressure  of  fresh  water  when  the  latter  is  at  rest. 

If  a  cistern  forms  a  cube,  and  each  side  is  1  foot  long,  the 
weight  of  water  the  cistern  would  hold  when  full  is  624  Ib. 
This  value  also  represents  the  pressure  which  would  be  exerted 
on  the  bottom  of  the  cistern,  but  as  its  sides  are  acted  upon  as 
well,  the  total  pressure  exerted  by  the  water  is  not  synonymous 
with  its  weight. 

Under  the  force  of  gravity,  pressure  is  due  to  head  of  water, 
and  upon  any  unit  area  in  a  horizontal  plane  the  pressure  is 
the  same.  For  example,  if  a  cistern  is  4  feet  deep,  and  is  filled 
with  water,  the  internal  pressure  on  the  bottom  per  square 
foot  of  surface  equals  624x4  =  249*6  Ib.  On  a  vertical 
surface  the  pressure  varies  with  the  depth  of  water,  being 
zero  at  the  water  level,  and  a  maximum  along  the  bottom 
edge. 

In  Fig.  219,  the  lengths  of  the  horizontal  broken  lines  which 
are  enclosed  by  the  triangle  ABC  represent  pressures  at  different 
depths,  BC  being  equal  to  AB,  or  to  the  depth  of  water  in  the 
tank.  To  calculate  the  pressure  on  a  vertical  surface,  it  is 
necessary  to  know  the  average  head  of  water  which  acts  upon 
that  surface.  For  example,  the  average  head  on  the  side  AB,  Fig. 

219,   is    — -y- ,  or  half  the  depth  of  the  water.     Should  the 

Lt 

average  head  be  required  for  a  portion  of  a  vertical  surface 
such  as  ef,  Fig.  219,  then  this  would  be  l~I  2  where  \  and  h2 
represent  the  heads  upon  e  and  /  respectively.  If  \  =  2  feet 

340 


HYDROSTATICS   AND    HYDRAULICS 


341 


and  7fc2  =  3  feet,  the  pressure  acting  upon  each  square  foot  of 

24-3 
surface  between  the  points  given  equals  -    -  x  62*4  =  156  Ib. 

a 

As  the  pressure  per  sq.  foot  per  foot  of  head  is  equal  to 
62*4  Ib.,  the  pressure  per  sq.  inch  for  each  foot  of  head  equals 

62-4      .00  IK 
_  =  -4331b. 

If  a  closed  receptacle,  such  as  a  cylindrical  tank  or  boiler, 
be  supplied  with  water  from  an  overhead  cistern,  the  pressure 
of  the  water  is  transmitted  over  the  whole  internal  surfaces  of 
the  vessel,  and  the  intensity  of  the  pressure  at  any  point  is 

A 


m  c 

FIG.  219. — Diagram  illustrating  water  pressure. 

proportional  to  the  head  of  water  above  that  point.  On  any 
given  horizontal  surface,  pressure  is  transmitted  over  the  whole 
area  with  undiminished  force,  and  it  acts  at  right  angles  to  the 
surfaces.  The  length  and  diameter  of  a  supply  pipe  in  no  way 
affects  the  pressure  transmitted  upon  a  surface,  when  water  is 
at  rest,  although  both  size  and  length  materially  affects  the 
discharging  capacity  of  a  pipe.  From  this,  it  becomes  clear 
that,  if  pressure  is  transmitted  upon  a  horizontal  surface  by 
means  of  a  supply  pipe,  the  total  pressure  on  that  surface  is 
equal  to  the  weight  of  water  contained  in  a  cistern  whose  plan 
is  the  same  as  the  surface,  and  whose  depth  is  equal  to  the 
head  of  water  under  consideration. 


342      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

For  determining  pressures  the  following  formulae  may  be 
used  :  — 

P  =  A  x  62-4  x  h       •  '  .':  ""'"'  .  "     .     ;  ;;  '     ,'       .     (47) 
.        .;       •.--;      >;-,..;  (48) 
.         .         .         .       ...••-'-   .'   (49) 

Where  P  =  total  pressure  in  Ibs. 

„      p  =  pressure  in  Ibs.  per  sq.  inch. 
„     A  =  sectional  area  of  surface  in  sq.  feet. 
„      a  =  sectional  area  of  surface  in  sq.  inches. 
„      7i  =  head  of  water  in  feet. 

For  the  formulas  given  it  is  necessary  to  either  find  the  area 
of  a  surface  or  to  substitute  values  which  produce  it,  but 
modified  formulae  may  be  used  for  special  cases.  Thus,  to 
determine  the  pressure  on  the  inner  surfaces  of  cylindrical 
vessels,  the  formulae  may  take  the  form  given  below. 

Formulae  for  determining  the  total  pressure  on  the  Sides  of 
Cylindrical  Vessels  — 

P  =  Dxl96xAxL   .        .        .      '.  '  .   -.        .    (50) 
.        .        ,        .  .    (51) 


Formulae  for  obtaining  total  pressures  on  the  ends  of 
Cylindrical  Vessels  and  on  Pistons,  etc.  — 

:.  ...     ,        ..    :|        .  (52) 

.  ;        ?        .      :\        .  (53) 
p 

from  which,  h  =  ^2^34  •  •  C54) 

Where  P  =  total  pressure  in  Ibs. 
„      D  =  diameter  in  feet. 
„      d  =  diameter  in  inches. 
„      h  =  head  of  water  in  feet. 
„      L  =  length  of  pipes  or  cylinder  in  feet. 
„       I  =  length  of  pipes  or  cylinder  in  inches. 
A  few  worked  examples  will  aid   to  show  the  range  of 
problems  to  which  the  above  rules  may  be  applied. 

Example  24.  —  Find  the  total  distributed  pressure,  and  the 
average  pressure  per  square  inch,  on  the  vertical  surface  of  a 
copper  hot-water  tank  which  is  1  ft.  9  in.  diameter  and 


HYDROSTATICS    AND    HYDRAULICS  343 

3  ft.  6  in.  high,  when   the   head  of  water  above  the  centre 
of  the  cylinder  is  36  feet. 

Using  Kule  50,  P  =  Dx  196  x^xL. 
Substituting  values  given,  P  =  If  x  196  x  36  x  3|  ; 
/.  P  =  43,218  Ib.  total  distributed  pressure  on  vertical  surface. 

For  the  second  part  of  the  problem  use  Formula  49. 
Where  p  =  hx  '433, 

^  =  36x433; 
.\p  =  15-58,  or  about  16  Ib.  per  sq.  inch. 

Example  25.  —  If  a  6-inch  diameter  drain  is  tested  for 
soundness  by  the  hydraulic  test,  determine  the  total  force 
which  tends  to  displace  the  stopper,  if  the  latter  is  subjected 
to  a  mean  head  of  12  feet  of  water. 

By  Formula  53,  P  =  &  x  '34  x  h. 
Substituting  values  given,  P  =  62  x  '34  x  12  ; 

.*.  P  =  146-88,  or  nearly  147  Ib. 

Example  26.  —  What  is  the  total  distributed  pressure  which 
acts  upon  one  side  of  a  cistern  which  is  6  ft.  6  in.  long,  4  ft. 
6  in.  wide,  and  3  ft.  9  in.  deep  ?  The  highest  water  level  is 
3  inches  below  the  top  of  cistern. 

3'  9"  —  3" 

Average   head   on   side  =  -  —  ^  -  =  lf  feet,  and  area  of 

surface  pressed  upon  =  6Jx3J. 

Using  Formula  47,  P  =  A  x  624  x  h. 
Substituting  values  given,  P  =  6  J  x  3£  x  624  x  If  ; 
/.  P  =  2484-3  Ib. 

Example  27.  —  A  dead-weight  safety  valve  is  loaded  to  the 
extent  of  6  Ibs.  Assuming  the  valve  orifice  is  -f-  inch  diameter, 
find  the  head  of  water  which  will  exert  pressure  equal  to  the 
load  given. 

Formula  54  gives  A  =  -^ 
" 


Substituting  values  given,  h  = 


X  * 

/» 


x  ** 

=  4517,  or  say  45  feet 


344     DOMESTIC   SANITARY   ENGINEERING    AND    PLUMBING 

In  the  last  problem  the  load  on  the  valve  represents  the 
pressure  which  tends  to  close  it,  and  therefore  takes  the  value 
of  P  as  shown. 

Hydraulics  is  that  branch  of  science  which  treats  on 
liquids  when  in  motion.  To  put  water  into  motion,  a  certain 
amount  of  pressure  is  required,  which  depends  upon  the 
nature  and  magnitude  of  the  resistances  to  be  overcome. 

If  a  house  is  supplied  by  water  from  a  tank  in  an  elevated 
situation,  the  pressure  of  the  water  at  any  point  in  the  supply 
pipe,  provided  the  water  is  at  rest,  is  equal  to  the  vertical 
distance  between  that  point  and  the  surface  of  the  water  in 
the  supply  tank.  Should  a  draw-off  tap,  however,  be  partly 
opened,  the  water  in  the  pipe  is  put  into  motion,  and  the  pressure 
is  reduced.  If  the  tap  is  opened  wide,  the  pressure  in  the 
pipe  is  still  further  reduced. 

The  principal  factors  which  require  taking  into  account 
when  ascertaining  the  flow  of  water  through  pipes  and  orifices 
are  as  follows : — 

(a)  Pressure  absorbed  in  overcoming  the  inertia  of  the 
water  and  putting  it  into  motion. 

(6)  The  form  the  outlet  orifice  takes. 

(c)  Pressure  absorbed  by  pipe  friction. 

(d)  Pressure  absorbed  by  sudden  contractions  in  pipes,  and 

by  abrupt  changes  of  direction. 

When  pipes  are  of  considerable  length,  the  pressure 
absorbed  by  (a)  and  (b)  is  a  negligible  quantity,  as  it  is  so 
small  when  compared  with  that  absorbed  by  pipe  friction.  On 
the  other  hand,  the  pressure  absorbed  by  (a)  and  (b)  when 
pipes  are  short  is  of  more  importance,  as  it  may  represent  a 
large  percentage  of  the  total  pressure. 

The  form  of  an  orifice  affects  the  rate  of  discharge,  because 
the  stream  lines  converge  to  a  more  or  less  extent  to  form 
a  contracted  neck — vena  contrata — just  beyond  the  opening 
through  which  the  stream  lines  issue,  and  instead  of  the 
sectional  area  of  flow  being  equal  to  that  of  the  orifice,  it  is 
only  equal  to  the  area  of  the  contracted  part.  It  is  not,  of 
course,  possible  to  measure  the  point  of  greatest  contraction 
for  different  forms  of  orifices  under  ordinary  conditions,  but, 
as  there  is  a  Definite  relation  between  the  area,  of  contraction 


HYDROSTATICS   AND    HYDRAULICS 


345 


and  that  of  an  orifice,  the  latter  is  expressed  as  a  ratio  of  the 
former,  and  termed  a  coefficient.  Thus,  for  a  short  tube  of 
1  inch  diameter,  the  stream  at  the  point  of  greatest  contraction 

measures  *9  or  ^  inch  diameter,  and  the  ratio  of  the  area  of 

.92 
the  tube  to  that  of  the  contracted  neck  is  -^-  =  '81. 

Suppose  now  we  require  to  find  the  discharge  through  a 
short  tube,  when  the  water  at  the  point  of  greatest  contraction 
has  a  velocity  of  v  feet  per  second,  and  where  A  equals  the 
area  of  the  tube  in  feet.  The  volume  of  water  discharged  by 
the  tube  would  equal  '81  xvxa  =  cubic  feet  per  second.  Mul- 


FIG.  220. — Illustrating  head  of  water  above  orifice. 

tiplying  by  '81  makes  the  necessary  correction  for  the  stream 
lines  in  this  case. 

Coefficient  for  orifice  in  thin  plate   .         .      =  *62 
„  „  good  shaped  nozzle  .         .      ='94 

„  „   short   tube   where   length 

equals  2  to  3  diameters       =  '81 
„  „   short   tube   where  length 

equals  4  to  12  diameters   =  '77 
„  „   short   tube   where   length 

equals  13  to  24  diameters   =*73 

Plow    of   water   through  Orifices  and  Short  Tubes. — The 
maximum  velocity  with  which  water  issues  through  an  orifice 


346      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

or  short  tube  in  the  side  of  a  cistern,  Fig.  220,  is  nearly  the 
same  as  that  acquired  by  a  body  which  has  fallen  from  rest 
through  a  height  h,  which  is  measured  from  the  centre  of  the 
orifice  to  the  water  surface. 

The  velocity  of  a  falling   body  is   found   by  the  general 
formula  — 

v  =  V2fii       --        .        -        -  *    (55) 

Where  v  =  velocity  in  feet  per  second. 
„      g  =  force  of  gravity  =  32*2. 
„      li  —  height  fallen  through  in  feet. 

For  finding  the  discharge  in  gallons,  the  velocity  formula 
may  be  modified  to  take  the  form  beneath. 

G  =  d2xl6-3xcxV£     .  .    (56) 

Where  G  =  gallons  discharged  per  minute. 
„      d  =  diameter  of  orifice  in  inches. 
„      c  =  coefficient    which    varies    with    the    form    of 

orifice.     (See  page  345.) 
„      h  =  head  of  water  above  centre  of  outlet. 
Further  simplification  is  possible  for  formulae  in  connection 
with  any  special  form  of  aperture  ;  thus,  for  a  short  tube,  where 
c  =  '81  the  two  constants  may  be  multiplied  together,  when 
we  have   16*3  x  81  =  13*2.     In  practice  the  decimal  may  be 
omitted  and  the  value  taken  as  13. 
Formula  for  Short  Tube.  — 

G  =  d2xl3xVA      .        .        .        .    (57) 

/  -  G  -  ' 

By  transposition  d  =  /u  ^—  .        .        .        „     (58) 

A 

•'      .•-..    (59) 


Example  28.  —  If  a  short  tube  of  1J  inch  diameter  is  under 
a  constant  head  of  2  ft.  6  in.,  find  its  rate  of  discharge.  (See 
Fig.  220.) 

By  Formula  57,  G  =  d2  x  13  x  Vh. 

Substituting  values  given,  G  =  (1  J)2  x  13  x  V2-K 

G-5X5     13     158. 

~4X4     T'  IS" 
.'.  G  =  32*09,  or  say  32  gallons  per  minute. 


HYDROSTATICS    AND    HYDRAULICS  347 

Example  29.  —  What  head  of  water  would  be  necessary  to 
discharge  15  gallons  per  minute  through  a  short  tube  of 
1  inch  diameter  ? 

By  Formula  59,  A  = 


15 


/.  h  =  1-33  feet,  or  say  1  ft.  4  in. 

Flow  of  Water  through  Long  Pipes.  —  When  water  is 
flowing  through  pipes  of  more  or  less  considerable  length,  the 
chief  resistance  is  that  offered  by  the  surfaces  of  the  pipes. 
The  velocity  of  a  particle  of  water  varies  according  to  its 
distance  from  the  surface  of  a  pipe,  its  velocity  being  greatest 
at  the  centre,  and  the  least  against  the  surfaces  of  the  pipe. 
Because  the  velocity  throughout  the  cross  section  is  not 
uniform,  the  size  and  condition  of  a  pipe  have  a  marked  effect 
upon  its  average,  or  mean  velocity  of  flow. 

Speaking  generally,  when  water  is  flowing  through  a  pipe 
its  mean  velocity  is  proportional  to  the  square  root  of  its 
hydraulic  mean  depth,  to  the  square  root  of  the  pressure 
head,  and  inversely  proportional  to  the  square  root  of  its 
length. 

By  the  aid  of  the  following  formulae  many  problems  in 
connection  with  long  pipes  may  be  solved.  These  make 
allowance  for  bends  in  pipes,  when  the  latter  are  laid  or  fixed 
in  the  usual  manner. 

Formulae  for  Long  Pipes.— 


(60) 


•     •     •     •     •     •     •  <63> 


348      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

Where  G  =  gallons  discharged  per  minute. 
„      d  —  diameter  of  pipe  in  inches. 
„      li  —  head  of  water  in  feet. 
„       I  =  length  of  pipe  in  feet. 

„      /=a  coefficient  which  varies  with  the  size  of  pipes, 
and  is  given  in  the  following  table : — 


TABLE  VIII 

VALUES  OF  / 

Lead  pipes  from    ^  inch  to  1    inch  diameter 

/=210 

,       li      , 

U     , 

.        . 

/=260 

Iron 

> 

u    » 

14 

3 

, 

. 

/=210 

M 

2         , 

3 

j 

i 

• 

/=330 

}» 
II 

• 

34       , 

54       , 

5 

7 

' 

/=460 
/=570 

To  use  Formulae  60  to  62  easily,  a  knowledge  of 
logarithms  is  necessary,  but  for  those  who  are  not  familiar 
with  this  branch  of  mathematics,  problems  may  be  solved  by 
the  aid  of  the  table  below. 


TABLE  IX 


Diameter 
pipe. 

5th  power  diameter. 

Diameter 
pipe. 

5th  power  diameter. 

4  inch. 

•03125 

3|  inch. 

525-218 

2 

•2373 

4 

1,024-000 

1-0000 

4i 

1,845-281 

li 

3-0517 

5 

3,125-000 

14 

7'594 

54 

5,032-843 

2 

32-000 

6 

7,776-000 

24 

97-656 

64 

11,602-906 

3 

243-000 

7 

16,807-000 

When  a  pipe  is  used  for  conveying  water  from  a  storage 
tank  T  to  a  point  P,  Fig.  221,  and  when  discharging  full  bore, 
the  head  absorbed  by  friction  at  different  points  of  the  pipe  is 
represented  by  the  vertical  distances  between  the  hydraulic 
grade  line  No.  1,  and  the  horizontal  line  L;  the  latter  repre- 


HYDROSTATICS    AND    HYDRAULICS 


349 


sents  the  level  of  the  water 
in  the  supply  tank.  The 
vertical  distances  between 
No.  1  hydraulic  grade  line 
and  the  water  pipe  indicate 
the  pressure  at  any  point 
when  the  pipe  is  discharging 
full  bore.  The  hydraulic  grade 
line  simply  indicates  the  level 
to  which  water  would  fall  in 
vertical  tubes,  were  it  prac- 
ticable to  obtain  them  suffi- 
ciently long  and  to  join  them 
with  the  pipe  in  question. 

In  Fig.  221  the  pipe  is 
supposed  to  be  of  uniform 
bore  from  end  to  end,  and  the 
hydraulic  grade  line  is  shown 
to  form  a  straight  line  from 
T  to  P.  A  true  hydraulic 
grade  line,  however,  like  the 
one  shown,  can  only  be  ob- 
tained when  the  whole  of  the 
pipe  line  is  below  it. 

Example  30.  —  Find  the 
gallons  discharged  per  minute 
by  a  3-inch  cast-iron  pipe  at 
the  point  P,  Fig.  221,  when 
the  head  of  water  and  length 
of  pipe  are  as  shown. 

Total  head  of  water  avail- 
able above  P  =  360 -100  = 
260  feet. 

Length  of  pipe  given  is 
6500  feet. 

By  Formula  60, 


G=     /rf*xj 

V 


350     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

In  Table  VIII.  it  will  be  found  that  the  value  of  /  for  a 
3-inch  pipe  is  330,  and  in  Table  IX.  the  5th  power  of  a  3-inch 
pipe  =  243. 

26Q  ' 


Substituting  values,  G=  ^/243 


.-.  G  =  56'6,  or  say  57  gallons  per  minute. 

In  this  calculation  the  whole  of  the  head  has  been  utilised 
in  discharging  57  gallons  per  minute  at  point  P.  Suppose, 
however,  a  discharge  under  a  given  pressure  is  required  at 
P;  under  the  latter  conditions  the  whole  of  the  260  feet 
of  head  would  not  be  available  for  forcing  the  water  through 
the  pipe,  and  the  hydraulic  grade  line  would  require  to  be 
raised. 

Example  31.  —  What  diameter  of  pipe  would  be  required  to 
discharge  100  gallons  per  minute  under  a  pressure  of  50  Ib. 
per  sq.  inch,  at  P,  Fig.  221,  when  the  length  of  pipe  and  head 
are  as  shown  ? 

The  equivalent  of  50  Ib.  per  sq.  inch  is  50x2-31  =  115-5 
feet  head.  The  value  2'31  represents  the  head  in  feet  which 
exerts  a  pressure  of  1  Ib.  per  sq.  inch. 

For  delivering  the  volume  required,  the  head  available  will 
be  360-(100  +  115-5)  =  144-5  feet. 


Now  by  Formula  62,  d= 

The  value  of  /,  however,  is  a  variable  quantity,  and  we  do 
not  know  the  precise  value  to  assign  to  it  when  beginning  the 
problem.  It  is  therefore  necessary  to  select  a  trial  value  of/, 
and  if  it  does  not  agree  with  the  diameter  obtained,  as  shown 
in  Table  VIIL,  the  problem  must  be  reworked  with  either  a 
lower  or  a  higher  value,  as  may  be  found  necessary.  We  will 
assume  the  diameter  required  is  somewhere  between  3J  and 
5  inches,  and  for  this  range  the  value  of  /  in  Table  VIII.  is 
given  as  460. 


/ 

Substituting  values,  d  =     I 


5/1002x6500 
460"  x 144-5 ' 


HYDROSTATICS    AND    HYDRAULICS  351 

Working  by  logarithms — 

Log.  1002  =4  Log.  460    =2-6628 

Log.  6500  =  3-8129         Log.  144'5  =  2-1599 
7-8129  4-8227 

4-8227 

5th  root  5)2-9902 
•5980 

Antilog.  -598  =  3-963; 
.-.  d  =  3'9*63,  or  say  4  inches  diameter. 

This  problem  may  be  worked  by  ordinary  arithmetic  with 
the  aid  of  Formula  63  and  Table  IX. 

By  Formula  63,  c?5 


Substituting  values  as  before,  d5  = 


fxh' 
1002x6500 


460  x  144-5  ' 
.-.  d5  =  977-8. 

Upon  reference  to  Table  IX.  it  will  be  found  that  the  5th 
power  of  3J  =  525;  this  value,  however,  is  too  low,  and  the 
diameter  which  agrees  with  the  next  higher  value  is  the  size 
required. 

As  before,  the  pipe  required  is  of  4  inches  diameter. 

When  water  is  discharged  at  the  point  of  escape  under  a 
pressure  of  50  Ib.  per  sq.  inch  for  the  conditions  shown  in 
Fig.  221,  the  hydraulic  grade  line  is  raised  to  the  position 
occupied  by  the  straight  line  No.  2. 

If  a  pipe  line  follows  the  general  configuration  of  the  earth's 
surface,  as  in  Fig.  222,  it  should  form  two  sections  of  different 
diameters.  The  first  section  would  be  from  A  to  B,  and  the 
other  from  B  to  C,  each  having  its  own  hydraulic  grade  line  as 
shown.  If  a  certain  volume  is  required  per  minute  at  C,  it  is 
obvious  that  a  similar  volume  must  first  be  delivered  in  the 
same  time  at  B.  When  comparing  the  two  sections,  that 
from  A  to  B  is  8200  feet  long,  and  the  maximum  head  above 
the  latter  point  is  35  feet;  for  the  section  BC  the  total 
length  is  650  feet,  and  the  vertical  distance  between  B  and  C 
is  185  feet.  Thus  the  head  for  the  shorter  section  is  more 
than  5  times  that  for  the  longer  section,  and  it  becomes  obvious 


352     DOMESTIC   SANITARY   ENGINEERING   AND   PLUMBING 


that,  in  order  for  the  longer  section 
to  deliver  a  volume  equal  to  the 
discharging  capacity  of  the  shorter 
section,  the  former  must  be  of  a  larger 
size. 

Should  a  pipe  from  A  to  C,  Fig. 
222,  be  of  uniform  bore,  the  length 
BC  would  be  never  fully  gorged.  A 
straight  line  from  A  to  C,  as  shown 
by  the  dotted  line,  would  not  be  a  true 
hydraulic  grade  line,  because  it  falls 
below  the  pipe  which  rises  to  B,  and 
under  such  circumstances  would  have 
a  negative  value. 

Assuming  that  a  pipe  of  uniform 
bore  were  used  for  the  conditions  given 
in  Fig.  222,  the  maximum  head  avail- 
able for  forcing  water  through  the 
pipe  would  be  35  feet,  which  is  the 
vertical  distance  between  point  B  and 
the  level  of  the  water  in  the  tank. 

Example  32.  —  Assuming  a  line  of 
pipes  follows  the  general  contour  of 
the  ground  surface  as  in  Fig.  222, 
determine  the  sizes  of  the  pipes  to 
deliver  120  gallons  of  water  at  C, 
when  the  head  and  lengths  of  pipes 
are  as  shown. 

Total  head  for  section  AB  =  250 
-215  =  35  feet. 

Length  of  pipe  given  =  8200  feet. 
Pipe  for  Section  AB.  — 

By  Formula  63,  d*  =  91*1 


It  will  be  necessary  to  use.  a  trial 
value  for  /,  and  if  we  assume  the 
pipe  required  will  be  between  5  and 
7  inches  diameter,  the  value  of  /  from 
Table  VIII.  is  570. 


HYDROSTATICS    AND    HYDRAULICS  353 

Substituting  values  given,  d5=    *     X    "      ; 


From  Table  IX.  we  find  that  a  5J-inch  diameter  pipe  when 
raised  to  the  5th  power  =  5032*8,  but,  as  this  value  is  not  large 
enough,  the  diameter  which  agrees  with  the  next  high  value  is 
the  one  required  ; 

.*.  Pipe  for  section  AB  will  be  6  inches  diameter. 

Pipe  for  Section  BC.— 

Head  upon  C  from  point  B  =  215  -30  =  185  feet. 

Length  of  Section  BC  =  650  feet. 

By  Formula  63,  ^  =  5l^-Z. 
fxh 

As  this  pipe  will  be  smaller  than  the  one  for  section  AB, 
we  will  assume  that  its  diameter  will  lie  somewhere  between 
2  and  3J  inches.  For  this  range  of  sizes  the  value  of  /,  Table 
VIII.,  is  330. 

Substituting  values  given,  d5  =  — 


In  Table  IX.  we  find  that  the  nearest  diameter  when  raised 
to  the  5th  power  to  agree  with  the  above  value  is  3  inches  ; 

/.  Pipe  for  section  BC  will  be  3  inches  diameter. 

Short  Pipes.  —  When  pipes  are  short,  the  head  to  generate 
velocity  at  entry  requires  to  be  taken  into  account,  and  also 
that  absorbed  by  branches  and  special  fittings.  For  these 
conditions  the  head  absorbed  by  friction  may  be  obtained  by 
the  following  formula  :  — 

'        *        *       *  •     (64) 


Where  h  =  loss  of  head  in  feet. 

,        d  =  diameter  of  pipe  in  inches. 
„      G  =  gallons  discharged  per  minute. 
„       e  —  a  coefficient  from  Table  X. 
23 


354      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


TABLE  X. 


For  a  plain  pipe  end  in  a  tank     .         .         . 
,,     trumpet  shaped  end  of  pipe  in  tank 
„     right-  angled  branch  in  pipe         .. 
,,     plug  tap  when  branched  into  pipe      . 
,,     screw  down  tap  when  branched  into  pipe 


00  OO  VO 
VO  rH  C<1  -*  00 
i-H  i-H  rH  rH  rH 
II  II  II  II  II 


Tdia. 


SN^^5w*sC^SR?SSS«^S?^^ 

FIG.  223. — Flow  of  water  through  pipes. 

If  we  assume  that  water  is  withdrawn  from  an  overhead 
cistern,  as  in  Fig.  223,  where  the  draw-off  pipe  is  comparatively 
short,  the  resistances  offered  by  the  tap  and  by  the  pipe  end 


HYDROSTATICS    AND    HYDRAULICS  355 

in  the  cistern  may  influence  the  discharge  to  a  considerable 
extent. 

It  is  not  possible  to  directly  calculate  the  discharge  by  a 
short  pipe,  as  the  different  resistances  are  not  known  at  the 
outset.  An  indirect  method  is  therefore  adopted  for  calculating 
the  discharging  capacity  of  short  pipes,  which  consists  of  first 
ascertaining  the  total  head  to  yield  an  assumed  discharge. 
When  a  certain  head  is  known  to  give  a  required  discharge, 
the  discharge  for  any  other  head  can  be  obtained  by  pro- 
portion, so  long  as  the  conditions  with  regard  to  size  and 
length  of  pipes  remain  unaltered. 

The  discharging  capacity  of  pipes  and  fittings  varies  directly 
as  the  square  root  of  the  pressure  head.  If,  therefore,  it  is  found 
that  a  water  pipe  gives  a  discharge  of  6  gallons  per  minute 
when  under  a  head  of  9  feet,  the  same  pipe  would  discharge 

under  a  head  of  1  foot     x       =  2  gallons  per  minute,  and  for  a 
V9 

head  of  16  feet  -  —  ~  =  —  =  8  gallons  per  minute. 

Example  33.  —  Determine  the  volume  of  water  that  would  be 
discharged  in  10  minutes  by  a  plug  tap,  as  in  Fig.  223,  when 
the  tap  is  subjected  to  a  constant  head  of  12  feet.  The  dia- 
meter of  the  pipe  is  1  inch,  and  its  length  will  be  assumed  to 
be  28  feet. 

The  principal  resistances  to  be  considered  are  those 
due  to  — 

(a)  Water  entering  the  pipe. 

(b)  Length  of  pipe. 

(c)  Plug  tap. 

As  it  is  necessary  to  ascertain  the  head  absorbed  for  an 
assumed  discharge  before  the  actual  discharge  can  be  cal- 
culated, we  will  take  the  assumed  discharge  at  10  gallons 
per  minute. 

Head  absorbed  by  friction. 

(a)  Head  absorbed  by  water  when  entering  pipe. 


By  Formula  64,  h  = 
Value  of  e  from  Table  X.^1'58. 


356      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

,  ,    ...    ..  7     102xl-5S 

Substituting  values  given,  h  =  —  —  ^—  -  ; 

-L    X  £\)  I 

/.  h  =  -59  feet. 
(b)  Head  absorbed  by  length  of  pipe. 

By  Formula  61,  ^=S« 


Value  of  /for  a  1-inch  pipe  in  Table  VIII.  =  210. 

102  x28 
Substituting  values,  h  = 


.-.  h  =  13-33  feet. 
(c)  Head  absorbed  by  plug  tap. 

G2  xe 
Formula  64  gives  h^j—-^. 

Value  of  e  from  Table  X.  =  14. 
Substituting  values  given,  h  =  ^  -^=  ; 

-L    X  ^0  / 

.\h  =  '52  feet. 

Total  head  to  discharge  10  gallons  per  minute  =  '59  -fl3'33 
+  •52  =  14-44  feet. 

In  the  example  only  12  feet  are  available  as  the  pressure 
head,  so  the  discharge  for  this  head 

10  x  \/F2 

=  —  -r=  =  91  gallons  per  minute  ; 

/.  the  volume  discharged  in  10  minutes 
=  9-1x10  =  91  gallons. 

Suppose,  now,  we  work  Example  33,  by  omitting  the 
resistance  due  to  the  water  entering  the  pipe,  and  also  that 
offered  by  the  plug-cock. 

By  Formula  60,  G  = 


Substituting  values,  G  =  /v/l5x21Qxl2  ; 

/.  G  =  9'48  gallons  per  minute. 
In  ten  minutes  the  discharge  =  9'48  x  10  =  94'8  gallons. 


HYDROSTATICS    AND   HYDRAULICS  357 

The  simple  and  the  more  abstruse  method  of  solving 
Example  33  only  gives  a  difference  of  94'8  —  91  =  3'8  gallons, 
which  is  not  very  much.  The  difference,  however,  is  more 
marked  when  the  ratio  of  the  diameter  to  the  length  of  the 
pipe  is  less,  as  the  following  example  will  show  :  — 

Example  34.  —  Find  the  discharge  per  hour  by  a  1^-inch 
lead  pipe  when  arranged  in  a  similar  manner  to  that  given 
in  Fig.  223,  when  the  head  of  water  upon  the  plug  cock  is 
7  feet,  and  when  the  length  of  the  pipe  is  10  feet. 

Assume  a  discharge  of  20  gallons  per  minute. 
(a)  Head  absorbed  when  entering  pipe. 

By  Formula  64,  h  = 


Substituting  values,  ^ 

:.h  =  467  feet. 

(b)  Head  absorbed  by  length  of  pipe. 

G2x/ 
Formula  61  gives  "  =  ^  —  ^5. 

202  x  10 
Substituting  values,  h  = 


/.  h  =  2-025  feet. 
(c)  Head  absorbed  by  IJ-inch  plug  cock. 


202xl-4 
Substituting  values,  h  = 


.'.  h  =  414  feet. 
Total  head  absorbed  in  discharging  20  gallons  per  minute 

=  (-467  +  2-025  +  -414)  =  2-906  feet. 

As  the  actual  head  available  is  7  feet,  the  discharge  for 
this  would  be 

20  x    /7~ 
.--_^  =31*04  gallons  per  minute  ; 


/.  Gallons  discharged  per  hour  =  31'04x  60  =  18624  gallons. 


358      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

If  now  we  try  to  solve  the  problem  by  omitting  the  resist- 
ances (a]  and  (c),  and  ascertain  the  discharge  directly  by 
Formula  60, 


/dbxfxh 
we  have  G  =  y'  -  —4 . 


«xJk*'  i         n         /(li)5X  260x7 

bubstitutmg  values,  G  =  ^/  -      —  y~  —     - 


.-.  G  =  37*17  gallons  per  minute. 
And  discharge  per  hour  =  3717  X  60  =  2230*2  gallons. 

For  this  problem  the  two  methods  give  a  difference  of 
2230-2  -1862-4  =  367*8  gallons  per  hour. 

The  latter  example  clearly  shows  that  when  the  discharging 
capacity  of  short  pipes  is  required  the  total  resistances  should 
be  taken  into  account,  and  this  is  especially  necessary  when 
the  pipes  are  of  large  diameter. 

For  pipes,  however,  of  1J  inches  diameter,  and  for  smaller 
sizes,  and  where  their  lengths  exceed  400  diameters,  the 
smaller  resistances  may  be  omitted.  Formula  60  under  such 
conditions  will  give  their  discharge  with  sufficient  accuracy. 

Suppose  the  diameter  of  a  service  pipe  is  required  for 
filling  a  cistern  in  a  given  time,  when  the  water  in  the  main 
is  under  a  known  pressure  as  in  Fig.  224.  The  type  of  ball- 
cock  will  affect  the  rate  of  discharge  to  a  certain  extent,  but 
if  a  full-  way  cock  is  used,  and  the  service  pipe  is  of  moderate 
length,  the  retardation  offered  by  the  tap  when  fully  open  may 
often  be  neglected.  A  ball-cock,  of  course,  begins  to  close 
before  the  normal  water-line  is  reached,  unless  special  provision 
is  made  to  prevent  it.  The  pressure  head  above  the  point  of 
delivery  may  be  found  by  first  converting  the  Ibs.  pressure 
per  sq.  inch  into  equivalent  head,  and  afterwards  deducting 
the  vertical  distance  between  the  main  (where  the  pressure  is 
taken)  and  the  point  of  discharge. 

Example  35.  —  If  a  house  is  supplied  on  the  intermittent 
system,  find  the  size  of  pipe  required  to  deliver  15  gallons  per 
minute,  when  a  pressure  of  40  Ib.  per  sq.  inch  is  recorded 
where  the  service  pipe  joins  the  main.  The  length  of  the 
pipe  is  150  feet,  and  the  vertical  distance  between  the  main 
and  point  of  discharge  45  feet.  (See  Fig.  224.) 


HYDROSTATICS   AND    HYDRAULICS 


359 


To  solve  this  problem  it  will  be  necessary  to  assume  that 
the  pressure  is  constant  in  the  main. 

For  the  conditions  given 
the  pressure  head  above  the 
ball  tap  will  equal  (40  x  2'31) 
-45  =  47-4  feet. 


G2x/ 

^/jr*-' 

"r~°  ifti 

d  — 

S^ 

li                        "H**t                1 

S 

j  X  II 

Assume  the  size  required 

ies  between  1  inch  and  1  J  inch 

iameter  in   order   to  obtain 

value  for/,  which  according 

\ 
1 

o  Table  VIII.  will  be  260. 

i 

Substituting  values  given, 

| 

/5      152xl50. 

! 
i 

260x47-4' 

i 
i 

/.  f?5  =  2'73. 

i 

On  reference  to  Table  IX. 

i 

b   will    be    found    that    the 

I 

learest   size   when  raised   to 

"^ 

ts  5th  power,  which  satisfies 

$ 

73,  is  H  in.  diameter  ; 

? 

/.  1J  inch  is  the  diameter 

equired. 

The    theoretical   size   lies 

etween  1  inch  and  1£  inch 

- 

iameter,   but  of   course   the 

i 

/ 

____!_ 

^T 

y^^l^^^^^^^S^^3^^^^^^^^^/         &&^£$*^"                     ^\ 

/ 

5  it-  

^  • 

^-S 

FIG.  224. — Flow  of  water  through  service  pipes. 

higher  commercial  size  would  be  adopted,  and  this  would  com- 
pensate to  a  great  extent  for  the  retarding  influence  of  the  tap. 


360      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


Another  form  of  problem  may  now  be  attempted,  where 
the  pipes  are  arranged  as  in  Fig.  225. 

Example  36.  —  Determine  the  sizes  of  the  pipes  to  deliver 
simultaneously  6  gallons  per  minute  at  C  and  5  gallons  per 
minute  at  D.  The  vertical  distance  between  point  C  and  the 


A. 


*5!555^vvmmvmw^ 
Length  of  Pi|ae  to       / 
Brunch  J,  16  feeiv 


Ungfh  of  Branch,  £4  feet 


\ 


I       \ 
I        \ 


--{--  \ 


\ 

\ 

• 

\ 

\ 

' 

r                 M 

'»       1 

Length  of  branch   t\ 
from  J,  65  feet". 

No  2. 

FIG.  225. — Flow  of  water  from  an  overhead  cistern. 

average  level  of  the  water  in  the  supply  tank  is  11  feet,  and 
that  between  point  13  and  the  source  of  supply  43  feet. 
Branch  No.  1  is  24  feet  long,  No.  2  branch  65  feet  long,  and 
the  length  of  the  draw-off  pipe  to  J  is  18  feet. 

The  first  thing  to  consider  is,  that  during  the  period  of 
draw-off  adequate  pressure  is  maintained  to  properly  supply 
both  taps.  To  attain  this  end  it  is  essential  that  the  hydraulic 


HYDROSTATICS    AND   HYDRAULICS  361 

grade  line  for  the  main  draw-off  pipe  shall  not  fall  below  the 
bend  at  B.  Suppose  the  maximum  fall  is  fixed  at  3  feet,  then 
the  line  AB  will  represent  the  hydraulic  grade  line  for  the 
main  draw-off  pipe.  The  hydraulic  grade  line  for  branch  No.  1 
is  shown  by  the  line  from  B  to  C,  and  that  for  branch  No.  2 
by  the  line  from  B  to  D.  Having  decided  upon  the  hydraulic 
gradients,  the  sizes  of  the  pipes  can  now  be  determined. 
Size  of  Main  Draw-off  Pipe.— 

The  head  available  for  the  main  draw-off  is  the  vertical 
distance  between  A  and  B,  Fig.  225,  and  this  pipe  will  require 
to  discharge  6  +  5  =  11  gallons  per  minute.  The  length  of  pipe 
to  branch  J  is  given  as  18  feet. 

By  Formula  63,  d5  = 


II2  x  18 
Substituting  values  given,  d5 


x  o 
/.  d°  =  2-792. 

From  Table  IX.  we  find  that  2792  lies  between  the  5th 
power  of  a  1-inch  pipe  and  that  of  a  IJ-inch  pipe. 
.\  size  of  main  required  =  1^  diameter. 

The  value  of  /was  assumed,  and  it  is  found  to  satisfy  the 
answer  obtained.  Had  it  been  too  large  or  small  this  part  of 
the  problem  would  have  required  reworking. 

Size  of  Branch  No.  1.— 

The  head  available  for  this,  above  the  point  of  discharge,  is 
the  vertical  distance  between  B  and  C. 

Then  #- 


For  trial  value  of  /  assume   the   pipe   required  does  not 
exceed  1  incli  diameter,  when  by  Table  VIII./=210. 

Substituting  values,  d5  =  --       ^  ; 

ZLO  X  o 

.•.#=•514. 

Upon  reference  to  Table  IX.  '514  lies  between  the  5th  power 
of  a  f  -inch  pipe  and  that  of  a  1-inch  pipe  ; 

.-.  size  of  No.  1  branch  =  1  inch  diameter. 


362      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

Size  of  Branch  No.  2.  — 

The  head  above  the  draw-off  tap  on  this  branch   is   the 
vertical  distance  between  B  and  D,  Fig.  225. 


Assuming  the  diameter  is  less  than  1  inch,  then  by  Table 
VIII.  /=  210. 

a  u  £1  4.-         i        M      52x65 
Substituting  values,  d5  = 


In  Table  IX.  it  will  be  found  that  "193  lies  between  the 
5th  power  of  a  |-inch  pipe  and  that  of  a  f  inch  pipe ; 

/.  size  of  branch  No.  2  =  j  inch  diameter. 

Collecting  the  sizes,  we  have — 

Main  supply  pipe  to  J      .  .     1 J  inch  diameter 

No.  1  branch    .                  .  .     1       „           „ 

No.  2      „         .        .         .  .     f       „ 
In  each  case  the  pipe  is  a  trifle  larger  than  necessary,  so 

that  each  pipe  will  deliver  rather  more  water  than  asked  for 
in  the  question. 

THICKNESS  AND  STRENGTH  OF  PIPES 

The  thickness  of  a  cast-iron  pipe  for  withstanding  a  given 
pressure  is  usually  determined  by  some  empirical  formula, 
which  provides  a  margin  of  strength  for  slight  variations  of 
thickness  and  other  inequalities.  So  far  as  a  lead  pipe  is  con- 
cerned, its  strength  may  be  considered  without  much  error  to 
be  directly  proportional  to  its  thickness,  and  inversely  pro- 
portional to  its  internal  diameter.  The  thickness  of  wrought 
iron  and  copper  pipes  is  governed  more  by  the  form  the  joints 
take  than  by  the  internal  pressure  they  are  required  to  with- 
stand. In  the  case  of  lead  pipes  a  minimum  thickness  is 
necessary  to  resist  crushing  by  external  forces  and  to  allow 
for  the  making  of  bends. 


HYDROSTATICS   AND   HYDRAULICS 


363 


Formulae  for  Lead  Pipes — 
2x*xS 

d 

„    Pxrf 
fe~2^7        ' 


t  = 


dxY 
pxdxF 

2xS 


(65) 
.  (66) 
•  (67) 

(68) 


Where  P  =  bursting  pressure  in  Ibs.  per  sq.  inch. 
„      p  =  safe  working  pressure  in  Ibs.  per  sq.  inch. 
„       S  =  ultimate  strength  of  metal  per  sq.  inch. 
„      F  =  factor  of  safety. 
„      d  =  diameter  of  pipe  in  inches. 

The  factor  of  safety  varies  from  5  to  10,  and  these  values 
indicate  that  the  maximum  safe  working  pressures  are  from 
5  to  10  times  less  than  those  which  produce  fracture. 

TABLE  XI. 

AVERAGE  TENSILE  STRENGTH  OF  METALS  PER  SQUARE  INCH 


Copper 

31,000  Ib. 

Wrought  iron 

50,000  Ib. 

Cast  iron    . 

18,000   ,, 

\  Lead  . 

2,600  „ 

Cast  steel    . 

62,000   „ 

Tin     . 

4,500  „ 

The  formulae  for  lead  pipes  may  be  checked  by  the  follow- 
ing tests,  which  were  carried  out  for  the  writer : — 

TESTS  ON  LEAD  PIPES 


Test  No. 

Bore  of 
pipe. 

External 
diameter. 

Weight  per 
lineal  yard. 

Thickness    :     Bursting 
walls  of        pressure  per 
pipe.             sq.  inch. 

1 

^  inch. 

•92  inch. 

7  Ib. 

•21  inch.          1960  Ib. 

2 

i  „ 

1-23     „ 

11    ,, 

•24     „              1500   „ 

3 

i  „ 

1-54     „ 

16   „ 

•27     „              1340   „ 

364     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

Using  the  results  of  these  tests  for  obtaining  the  ultimate 
strength  of  lead,  we  have  by  Formula  66, 


Substituting  values  from  Test  No.  1, 


2x-21   : 
=  2333  Ib.  per  sq.  inch. 


Substituting  values  from  Test  No.  2, 

q_  ISQOxf 
=  2x-24  ' 


/.  S-2343  Ib.  per  sq.  inch. 

Substituting  values  from  Test  No.  3, 

s_  1340x1. 
=  2x-27   ' 

/.  S  =  2481  Ib.  per  sq.  inch. 

For  each  test  the  ultimate  strength  of  lead  has  a  different 
value,  but  this  is  chiefly  due  to  the  fact  that  lead  pipes  are 
seldom  perfectly  true  in  section,  especially  when  the  pipes  are 
of  small  bore.  The  strength  of  a  pipe  of  course  is  only  equal 
to  that  of  its  weakest  side.  In  Table  XI.  the  strength  of  lead 
is  given  at  2600  Ib.  per  sq.  inch.  Test  No.  1  gives  within 
11  per  cent,  of  that  value,  and  Test  No.  3  within  5  per  cent. 
From  these  results  we  may  infer  that  a  higher  factor  of 
safety  is  necessary  for  small  bore  pipes  than  for  those  of  larger 
diameter. 

Example  37.  —  Find  the  maximum  safe  working  pressure  for 
a  ^-inch  lead  pipe  which  weighs  7  Ib.  per  yard,  when  a  factor 
of  safety  8  is  adopted. 

By  Formula  67,  p  = 

The  value  of  t  in  the  table  of  tests  =  '21, 
whilst  s  in  Table  XI.  =  2600. 


HYDROSTATICS    AND    HYDRAULICS  365 

Including  these  values  and  the  others  given, 
2  x  -21x2600 

p=    T^r 

/.  p  =  27'3  Ib.  per  sq.  inch. 

Example  38. — Determine  the  thickness  for  a  Ij-inch 
diameter  lead  pipe  which  is  to  he  subjected  to  a  maximum 
pressure  of  45  Ib.  per  sq.  inch,  when  a  factor  of  safety  6  is 
adopted. 

Using  Formula  68,  t=pxdxY . 

2xs 

o  ,   . .,    , .          ,         .    45  x  H  x  6 
Substituting  values,  t=  — —  -        ; 

.-.  £  =  -078  inch  thick. 

Although  a  pipe  of  the  latter  thickness  would  withstand 
the  internal  pressure,  it  would  be  far  too  thin  for  a  water 
pipe,  its  weight  per  lineal  yard  being  a  little  less  than  5|  Ib. 
From  Example  38  we  see  that  Formula  68  is  not  suitable 
for  ascertaining  the  thickness  of  pipes  for  withstanding  either 
medium  or  low  pressures.  For  example,  a  IJ-inch  lead  waste 
pipe  which  weighs  12  Ib.  per  yard  has  a  thickness  of  '156  inch, 
and  with  a  factor  of  safety  6  would  be  capable  of  withstanding 
a  pressure  of  90  Ib.  per  sq.  inch. 

Formula  for  Cast-iron  Pipes — 

The  thickness  of  cast-iron  pipes  up  to  9  inches  diameter 
can  be  determined  by  the  formula  below. 

*  =  [{(-00014xd)xGt?+50)}  +  -27]     .       .      .     (69) 

Where  t  =  thickness  of  metal  in  inches. 

„     p  =  water  pressure  in  Ibs.  per  sq.  inch. 
„      d  =  diameter  of  pipe  in  inches. 

Evximple  39. — Find  the  thickness  of  a  6-inch  diameter  cast- 
iron  pipe  which  is  subjected  to  a  pressure  of  150  Ib.  per  sq. 
inch. 

By  Formula  69,  *  =  [{(-00014xd)x(p  +  50)}  +  -27]. 
Substituting  values,  *  =  [{(-00014  x  6)x(150  +  50)} +-27], 

£  =  [(•00084x200)  +  '27]; 
,-.  t  —  -438,  or  say  ^g-  inch  thick. 


CHAPTER   XIII 
DOMESTIC    HOT   WATER   SUPPLY 

Movement  of  Heat. — Heat  moves  in  three  ways :  (a)  by 
conduction  ;  (b)  by  convection ;  (c)  by  radiation.  To  heat  water 
in  an  apparatus  the  first  and  second  forms  of  heat  motion  come 
into  operation.  When  the  surfaces  of  a  boiler  are  exposed  to 
the  action  of  heat,  a  certain  amount  of  the  latter  is  transmitted 
through  the  plates.  In  other  words,  heat  is  conducted  through 
the  metal  walls  from  the  fire  to  the  water  side  of  a  boiler,  and, 
in  turn,  heat  is  absorbed  by  the  water  in  contact  with  the 
heated  surfaces.  The  transference  of  heat  from  receptacle  to 
receptacle  which  contains  water  is  accomplished  by  convection, 
when  suitable  passages  are  provided  through  which  the  water 
can  circulate. 

Circulation  of  Water. — Movement,  or  circulation,  of  the 
innumerable  particles  of  which  water  consists  takes  place  as 
soon  as  they  differ  in  weight,  the  more  heated  and  lighter 
particles  being  displaced  by  those  of  greater  density. 

In  order  for  water  to  freely  circulate  between  two 
receptacles,  such  as  a  boiler  and  a  tank,  two  separate  paths  are 
essential.  One  path  is  provided  through  which  the  heated 
particles  escape  after  being  heated,  and  the  other  conveys  the 
cooled  particles  to  the  source  of  heat. 

The  Tank  System. — Fig.  226,  although  not  often  installed, 
possesses  one  or  two  favourable  points.  In  the  first  place  the 
position  of  the  hot-water  tank  admits  of  a  cheap  form  of  tank 
being  used,  and  this,  accordingly,  reduces  the  cost  of  a  com- 
pleted system.  Instead  of  a  cylindrical  tank,  either  a  square 
or  rectangular  form  may  be  adopted.  Another  advantage 
possessed  by  the  tank  system,  is  that  a  free  outflow  of  water 
can  be  obtained  at  the  highest  draw-off  taps,  on  account  of  the 

366 


DOMESTIC    HOT   WATER   SUPPLY 


367 


water  being  withdrawn  directly  from  the  overhead  tank,  and 
owing  to  the  comparatively  short  lengths  of  pipe  through 
which  it  has  to  flow. 

The  tank  system,  however,  has  drawbacks.     The  tank  can 
be  emptied  by  any  of  the  draw-off  taps  should  the  supply  to 


FIG.  226. 

the  feed  cistern  fail,  and  when  water  is  withdrawn  at  a  tap  a 
mixture  of  hot  and  colder  water  is  frequently  obtained.  The 
latter  is  a  bad  feature  in  connection  with  the  tank  system, 
for  the  resultant  temperature  at  the  point  of  escape  may  be 
considerably  less  than  that  of  the  water  in  the  tank.  Of 
course,  when  the  draw-off  first  begins  the  water  which  oc- 


368      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

cupies  the  upper  part  of  the  boiler  will  be  at  a  higher  tern* 
perature  than  that  in  the  upper  part  of  the  tank,  and  if 
only  a  small  volume  is  withdrawn  the  hottest  water  may 
issue  at  the  point  of  escape.  On  the  other  hand,  when 
larger  volumes  are  required  the  heated  water  in  the  boiler  is 
soon  replaced  with  colder  water,  and  this  flows  to  the  point  of 
draw-off"  and  mixes  with  that  from  the  overhead  tank. 

With  regard  to  the  volume  of  the  water  which  will 
travel  by  each  path,  this  will  depend  entirely  upon  the 
resistance  offered,  the  greater  volume  naturally  flowing  by  the 
route  which  offers  the  least  obstruction.  As  a  rule  the  taps  at 
the  higher  levels  will  discharge  a  greater  percentage  of  hot 
water  directly  from  the  tank  than  taps  at  lower  points.  In 
Fig.  226  the  flow  and  return  circulating  pipes  are  shown  to 
take  a  very  favourable  course  between  the  boiler  and  the  tank, 
but  in  practice  the  course  is  usually  more  circuitous  than 
shown.  The  length  of  the  circulation  pipes  retards  the  move- 
ment of  the  water,  for  as  a  rule  these  pipes  are  only  of  small 
bore. 

Details  of  Tank  Systems. — It  will  be  observed  in  Fig.  226 
that  the  draw-off  branches  are  only  taken  from  the  flow-pipe, 
and  if  the  best  results  which  this  system  is  capable  of  yielding 
are  to  be  obtained,  the  flow-pipe  will  require  to  terminate  at  a 
fairly  high  point  in  the  tank.  In  some  cases  a  separate  draw- 
off  pipe  is  adopted  which  is  joined  half-way  up  the  tank.  With 
regard  to  the  cold  supply  to  tank  T,  it  will  improve  matters, 
where  the  relative  positions  of  the  pipes  are  as  shown,  if  the 
water  is  deflected  sideways  when  it  enters  the  tank  by  means 
of  an  elbow  or  tee.  This  arrangement  prevents  the  cold  water 
upon  entering  the  tank  from  taking  a  direct  course  to  the 
return  pipe  when  hot  water  is  being  withdrawn. 

The  connections  to  the  boiler  are  shown  at  the  top,  the 
return  being  continued  by  means  of  a  tube  to  near  the  bottom 
of  the  boiler.  It  is  not  practicable  in  every  case  to  make  the 
boiler  connections  in  the  position  shown,  and  it  is  often 
necessary  to  either  join  the  pipes  at  the  side  or  at  the  back. 

A  high  and  low  connection  to  a  boiler  is  not  essential  to 
make  the  water  circulate,  but  to  define  the  course  the  water 
should  take, 


DOMESTIC    HOT    WATER   SUPPLY  369 

Although  high  and  low  connections  with  boilers  are 
generally  made,  it  is  not  uncommon  to  find  that  reversed 
circulations  occur.  As  a  general  rule,  it  will  be  found  when  an 
intended  flow-pipe  acts  as  a  return,  and  vice  versa,  that  some 
form  of  retardation  has  been  introduced  in  connection  with  the 
flow-pipe.  The  flow-pipe  connection  should  provide  as  free  a 
passage  as  practicable  for  the  escape  of  the  heated  water,  and 
when  the  flow-pipe  is  either  joined  at  the  side  or  at  the  back 
of  a  boiler,  the  length  of  the  horizontal  pipe  in  the  immediate 
neighbourhood  of  the  boiler  should  be  reduced  to  a  minimum. 
If  a  portion  of  a  flow-pipe  must  be  horizontally  arranged, 
this  should  be  introduced  if  possible  above,  and  not  on  a  level 
with,  a  boiler. 

Where  a  tank  system  is  adopted,  and  it  is  deemed  necessary 
to  shorten  the  lengths  of  the  dead  branches  in  order  that  hot 
water  may  be  readily  obtained  after  the  opening  of  a  tap,  the 
piping  may  be  arranged  as  in  Fig.  227.  The  branch  circuit 
should  be  kept  as  short  as  possible,  and  the  pipes  should  have 
a  gradual  rise  towards  the  tank.  To  enable  water  to  circulate 
through  the  branch  in  the  direction  indicated  by  the  darts,  a 
stop  tap  s  should  be  introduced  immediately  above  the  branch 
at  B.  It  is  only  essential  for  a  small  portion  of  the  water  to 
circulate  through  the  secondary  circuit,  and  this  can  be  adjusted 
by  means  of  the  stop  tap  S. 

Cylinder  System. — For  heating  water  for  domestic  purposes 
the  cylinder  system  is  the  more  generally  adopted.  It  chiefly 
differs  from  the  tank  system  in  the  following  respects  : — 

(a)  A  cylindrical  tank  takes   the  place  of   the  square  or 

rectangular  one,  as  a  circular  shape  is  better  suited 
for  resisting  internal  pressure. 

(b)  Shorter  circulation  pipes  are  employed  on  account  of 

the  cylinder  being  located  nearer  to  the  boiler. 

(c)  The  cylinder  is  arranged  to  remain  full   or   partially 

charged  when  the  cold  supply  fails. 

In  Fig.  228  a  cylinder  system  is  shown  which  is  suitable 
for  a  small  dwelling,  and  all  the  connections  are  arranged  to 
give  good  results.  The  air  or  expansion  pipe  is  shown  to 
terminate  above  the  roof,  but  when  in  the  immediate  neigh- 
bourhood of  a  supply  tank  it  may  be  turned  over  so  as  to 
24 


370      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


discharge  into  it  as  shown  by  dotted  lines.  There  is  not 
often  any  objection  to  the  latter  method,  excepting  where 
the  temperature  of  the  cold  water  is  liable  to  be  appreciably 
raised,  and  when  cisterns  are  fixed  in  positions  where  the 
free  escape  of  steam  would  be  objectionable. 

All  draw-off  branches  in  a  cylinder  system  are  joined  to 
the  air-pipe,  (excepting  special  cases)  and  it  is  desirable  that 


TE&HE.  &KHBBML. 

(  WITH  SECONDARY  CIRCUIT  ^ 


FIG.  227. 


their  connections  be  made  well  below  the  bottom  of  the  cold 
supply  cistern,  to  prevent  air  entering  when  draw-  off  taps 
are  opened. 

To  enable  a  system  to  be  emptied  of  water,  a  pipe  is 
frequently  connected  with  the  boiler  as  in  Fig.  228,  the  free  end 
terminating  at  any  suitable  point.  A  stop  tap  C  should  be 
provided  on  the  cold  supply  pipe  so  that  the  water  can  be 
turned  on  and  off  as  required. 

On  account  of  the  diversity  of  views  which  prevail  with 


DOMESTIC    HOT    WATER    SUPPLY 


371 


regard  to  the  positions  the  connections  with  a  cylinder  system 
should  be  made,  it  may  be  well  at  this  point  to  discuss  some 
of  the  methods  of  arranging  the  pipes,  and  to  point  out  any 
merit  or  demerit  they  possess. 

In  Fig.  229  the  cold  supply  is  shown  joined  directly  with 
the   boiler,    this    method    being   largely   adopted    in    certain 


districts.  In  this  case^the  principal  thing  to  consider  is,  the 
final  temperature  of  the  water  when  discharged  at  any  point 
when  compared  with  that  in  the  cylindrical  tank.  When  a 
tap  is  opened,  water  will  flow  to  the  point  of  escape  from  any 
available  source,  and  when  the  pipes  are  arranged  as  in 
Fig.  229,  the  cold  water  upon  entering  the  boiler  can  flow  to 
the  cylinder  through  either  the  flow  or  return  pipe.  If  only 


372      DOMESTIC    SANITARY   ENGINEERING    AND    PLUMBING 


a  comparatively  small  volume  of  water  is  withdrawn  at  a 
time,  the  cold  supply  connection  as  arranged  will  answer 
fairly  well;  when,  however,  larger  volumes  are  withdrawn, 
the  hot  water  in  the  boiler  is  soon  displaced,  and  cold  water 
passes  through  the  flow  pipe  and  mixes  with  the  heated  water 
at  the  top  of  the  cylinder.  Should  the  flow  connection  be 
made  immediately  above  the  return,  the  water  in  the  upper 
part  of  the  cylinder  may  not  be  unduly  cooled  during  the 
period  of  withdrawal.  It  is,  however,  generally  desirable  for  a 


Wash-out  Cock 

FIG.  229. — Cylinder  system  Avhere  cold  water  supply  joins  directly 
with  boiler. 

flow-pipe  to  be  connected  at  a  high  point  of  the  cylinder,  as 
this  allows  a  limited  volume  of  very  hot  water  to  be  quickly 
obtained  after  a  fire  is  first  lighted.  If,  on  the  other  hand,  the 
flow  connection  is  made  at  a  low  point,  then  the  heat  trans- 
mitted from  the  boiler  in  a  given  time  is  diffused  throughout 
a  greater  mass  of  water,  and  consequently  it  is  raised  through 
a  smaller  range  of  temperature. 

No  fault  can  be  found  with  the  connections  in  Fig.  229 
so  far  as  the  heating  of  the  water  is  concerned,  but  the  fault 
occurs  when  a  moderate  volume  of  water  is  withdrawn. 


DOMESTIC    HOT    WATER   SUPPLY 


373 


It  is  frequently  contended  that  cold  water  should  not 
directly  enter  a  boiler  as  in  Fig.  229,  on  account  of  the  latter 
being  subjected  to  great  variations  of  temperature,  and,  in 
consequence,  a  greater  amount  of  strain.  This  point,  however, 
so  far  as  range  boilers  are  concerned,  is  not  of  much  importance, 
for  in  practice  the  life  of  a  boiler  does  not  appear  to  be  affected 
by  any  particular  arrangement  of  the  cold  supply. 

The  principal  advantage  offered  by  joining  the  cold  supply 
to  the  cylinder,  is  that  unnecessary  mixing  of  hot  and  cold 
water  can  be  prevented  when  water  is  withdrawn.  When 
the  cold  supply  is  joined, 
as  in  Fig.  228,  the  entering 
water  is  well  diffused  over 
the  lower  portion  of  the 
cylinder,  and  the  upper  and 
hotter  water  is  more  nearly 
uniformly  displaced. 

In  Fig.  230  the  flow 
connection  to  the  cylinder 
is  shown  joined  at  a  low 
point,  and  a  by-pass  is  pro- 
vided between  the  flow  and 
the  air-pipe.  For  a  simple 
system,  a  by-pass  offers  no 
special  advantage,  its  use 
being  only  intended  to  con- 
vey a  portion  of  the  hottest 
water  directly  to  the  top  of  the  cylinder.  As  a  rule  this 
can  be  better  accomplished  by  joining  the  flow-pipe  at  a 
higher  point. 

Secondary  Circuits. — Although  for  the  smallest  installa- 
tions secondary  circuits  are  not  required,  they  are  desirable 
in  large  buildings  to  avoid  long  dead  branches,  and  to  permit 
of  hot  water  being  withdrawn  immediately  after  opening  a 
tap.  A  secondary  circuit  is  shown  in  Fig.  231,  and  the  lower 
end  is  joined  about  6  inches  below  the  top  of  the  cylinder. 
In  order  for  water  to  circulate  through  the  secondary  circuit, 
the  latter  must  be  arranged  that  air  cannot  accumulate.  It  is 
not  essential  that  a  circuit  should  fall  from  the  main  air  or 


StobCbck. 

*<s  r 


FIG.  230. — Cylinder  system  with  by-pass 
between  flow  and  air  pipe. 


374     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


expansion  pipe,  provided  that  air  can  freely  escape  at  the 
head  of  the  circuit.  When  a  tap  is  opened  on  a  system  which 
is  arranged  like  Fig.  231,  water  can  flow  to  the  point  of 
escape  by  two  routes.  For  this  reason  it  is  desirable  that  the 


Circuit 


5SS5^5J5S^!«S^^ 


FIG.  231. — Cylinder  system  with  secondary  circuit. 

lower  end  of  the  secondary  circuit  be  joined  to  the  upper 
part  of  the  cylinder,  in  order  that  the  hottest  water  available 
may  be  withdrawn,  irrespective  of  the  path  the  greater  volume 
may  take. 

Occasionally  a  towel-rail,  coil,  or  small  radiator  is  joined 
to  a  secondary  return,  and  either  may  be  heated  satisfactorily 


DOMESTIC    HOT    WATER    SUPPLY  375 

provided  the  boiler  is  of  ample  power.  Should  a  towel-rail 
be  fixed  as  in  Fig.  231,  the  flow  connection  may  be  taken  from 
the  vertical  pipe,  and  the  return  from  the  rail  may  be  joined 
to  the  horizontal  pipe.  In  this  case  an  air-pipe  or  cock  is  not 
essential,  as  the  air  can  escape  from  the  rail  through  the 
higher  connection,  but  if  the  flow-pipe  should  join  at  the 
bottom  of  the  rail,  then  special  provision  for  the  escape  of  air 
would  be  necessary. 

When  a  coil  or  radiator  is  of  more  or  less  considerable 
distance  from  the  draw-off  taps,  it  may  be  desirable  to  provide 
a  separate  circuit  for  it.  Each  case,  however,  should  be  con- 
sidered on  its  own  merits,  and  when  the  laws  which  govern 
the  movement  of  water  through  pipes  are  thoroughly  under- 
stood there  is  no  difficulty  in  arranging  a  circuit  to  give  good 
results.  If,  for  example,  it  is  proposed  to  fix  a  radiator  in  a 
room  adjoining  a  kitchen,  the  former  in  many  cases  may  be 
heated  from  the  kitchen  range  or  other  fire  when  a  suitable 
boiler  is  used.  Assuming  that  a  radiator  is  fixed  on  the  floor 
as  in  Fig.  232,  it  will  be  necessary  for  the  water  to  circulate 
below  the  boiler,  but  this  will  present  no  difficulty  if  the  flow- 
pipe  is  taken  from  a  position  which  will  give  a  good  circulating 
head.  In  Fig.  232  a  separate  connection  is  taken  from  the 
boiler  to  heat  the  radiator,  and  this  is  generally  the  most 
satisfactory  course  to  adopt.  The  circulating  head  is  obtained 
by  rising  the  flow-pipe  several  feet  above  the  boiler,  and  from 
the  highest  point  of  the  circuit  the  return  passes  to  the 
radiator,  and  thence  to  the  boiler.  An  air-pipe  will,  of  course, 
be  necessary  at  the  head  of  the  circuit,  and  this  will  require 
to  terminate  above  the  level  of  the  water  in  the  supply 
cistern. 

With  regard  to  the  size  of  circuit  for  supplying  a  radiator, 
this  as  a  rule  should  not  be  less  than  1J  inches  diameter, 
on  account  of  the  resistance  offered  to  the  circulation  by 
the  length  of  the  pipe  and  the  column  of  cooled  water  in 
the  pipe  EF.  To  aid  the  circulation  the  horizontal  pipe  ED 
should  be  as  short  as  practicable,  although,  so  far  as  the 
horizontal  pipe  BC  is  concerned  a  greater  length  may  be 
advantageous,  in  order  that  the  water  may  be  further  cooled,  and 
so  give  a  greater  average  density  in  the  descending  column 


376      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

CD.     The  flow  and  return  on  the  left  side  of  Fig.  232  may 
join  with  a  cylinder  in  the  ordinary  manner. 

In  a  small  dwelling  the  cylinder  is  sometimes  located  in  a 
bathroom,  instead  of  near  to  the  kitchen  range ;  this  arrange- 
ment may  prove  advantageous  in  many  cases,  as  the  heat 
given  out  by  the  cylinder  may  be  utilised  for  airing  linen  or 
for  keeping  a  bathroom  warm  in  cold  weather.  A  cylinder, 
however,  when  fixed  some  distance  from  a  range  presents  a 
few  drawbacks  which  may  be  enumerated  as  follows  : — 


FIG.  232. — Cylinder  system  with  separate  circuit  for  heating  a  radiator. 

(a)  Longer  circulation  pipes  are  necessary. 

(&)  The  possibility  of  circulating  pipes  being  exposed  to 
a  draught  when  laid  beneath  floors,  and  the  possi- 
bility pf  them  being  choked  with  ice  in  frosty 
weather. 

(c)  Long  dead  branches  may  be  necessary. 

So  far  as  the  airing  of  linen  is  concerned,  this  can  be  done 
by  a  coil  of  pipe  when  joined  to  a  secondary  return,  but  this 
adds  to  the  cost  of  the  installation. 

The  objection  to  longer  circulation  pipes  can  be  partially 


DOMESTIC    HOT    WATER   SUPPLY 


377 


overcome  by  increasing  their  size,  but  often  this  is  not  taken 
into  account. 

A  typical  example  of  a  cylinder  when  fixed  on  the  first 
floor  of  a  building  is  shown  in  Fig.  233.  For  the  conditions 
shown  it  would  be  useless  to  join  the  secondary  return  just 
below  the  top  of  the  cylinder  as  indicated  by  the  dotted  line  L, 
for  water  would  lie  stagnant  in  the  pipe  excepting  when  a 
draw-off  tap  was  opened.  To  cause  the  water  to  circulate 
through  an  arrangement  like  that  shown  in  Fig.  233,  the  lower 
end  of  the  secondary  circuit  may  be  joined  with  the  return  to 
the  boiler.  Water  is  prevented  from  flowing  from  the  bottom 


FIG.  233. — Cylinder  system  with  secondary  circuit. 

of  the  cylinder  when  a  draw-off  tap  is  opened  (say  at  D)  by 
means  of  a  non-return  valve.  As  these  valves  are  liable  to 
get  out  of  order,  it  is  desirable  to  prevent  as  far  as  possible 
any  ill-effect  from  this  cause.  Should,  however,  a  valve  get 
out  of  order,  the  trouble  during  the  period  of  draw-off  would 
be  minimised  if  the  size  of  the  circuit  was  reduced  after 
passing  the  last  draw-off  branch  D,  as  in  Fig.  233. 

To  reduce  the  size  of  the  secondary  circuit  before  the 
non-return  valve  is  reached  would  retard  the  circulation  of 
the  water,  but  that  is  not  of  paramount  importance  in  the 
case  shown.  The  object  of  a  secondary  return  is  simply  to 


378      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

reduce  the  length  of  dead  branches,  and  it  matters  little 
whether  the  water  in  the  secondary  return  is  kept  in  a  heated 
state  by  either  a  quick  or  a  slow  rate  of  circulation.  Farther, 
if  it  is  deemed  desirable  to  increase  the  circulating  head  in  the 
secondary  return,  the  latter  may  join  the  main  return  nearer 
to  the  boiler. 

A  suitable  form  of  non-return  valve  for  fixing  on  a  hori- 
zontal pipe  is  given  in  Fig.  234,  but  the  flap  should  be  made 
as  light  as  possible.  Other  forms  may  be  obtained  for  vertical 
pipes,  but  the  latter  unduly  retard  the  circulation  and  should 
not  be  used. 

In  tenement  dwellings,  where  each  flat  is  provided  with  a 


FIG.  234. — Reflux  or  non-return  valve. 

separate  system  of  hot  water  supply,  the  cold  water  supply 
from  one  overhead  cistern  may  be  utilised  for  a  number  of 
cylinders,  or  each  system  may  have  its  own  cold  supply  tank, 
as  in  Fig.  235.  When  the  latter  method  is  adopted,  one 
common  air-pipe  is  generally  employed  into  which  the  air-pipe 
from  each  cylinder  is  joined.  The  junction  with  the  main  air- 
pipe  should  not  be  much  less  than  9  inches  above  the  highest 
water  level  of  the  cold  supply  tank,  in  order  to  prevent  the 
overflow  of  hot  water  through  expansion.  The  top  of  the  main 
air-pipe  should  terminate  above  the  roof  or  other  suitable 
place,  and  the  bottom  of  the  air-pipe  may  terminate  at  any 
suitable  point  beneath  the  lowest  cylinder. 

The  draw-off  pipe  A,  Fig  235,  on  account  of  its  being  only  a 


DOMESTIC    HOT   WATER    SUPPLY 


379 


short  distance  below  the  bottom  of  the  supply  tank,  often 
allows  air  to  be  discharged  with  the  water,  which  issues  in  an 
irregular  or  jerky  manner  at  the  point  of  escape. 


FIG.  235. — Cylinder  system  for  tenement  buildings  where  each  flat  is 
provided  with  a  cold-water  supply  tank. 

To  prevent  air  gaining  access  to  a  draw-off  branch,  either 
the  pipes  must  be  graded  as  regards  their  size,  or  the  principal 
draw-oft'  pipe  may  be  joined  about  6  inches  below  the  top  of  the 
cylinder,  as  at  B,  Fig.  235. 


380     DOMESTIC    SANITARY    ENGINEERING   AND   PLUMBING 

Square  or  rectangular  tanks  may  be  used  in  lieu  of 
cylindrical  ones  for  an  arrangement  like  Fig.  235,  as  the 
pressure  upon  them  is  small. 

The   more  general   method   of   arranging   the   hot   water 


FIG.  236. — Cylinder  system  for  tenement  buildings  where  cylinders 
are  supplied  from  one  overhead  tank. 


CF 


DOMESTIC   HOT   WATER   SUPPLY  381 

supply  for  tenement  dwellings  is  shown  in  Fig.  236,  where  a 
separate  supply  pipe  to  each  cylinder  is  taken  from  an  over- 
head cistern.  This  arrangement  has  the  advantage  of  giving 
a  quicker  outflow  of  water  at  the  draw-off  taps  on  the  lower 
flats,  on  account  of  the  additional  pressure  to  which  they  are 
subjected.  For  the  highest  flats,  the  pipes  may  be  treated 
as  before  described,  to  prevent  air  flowing  along  with  water 
through  the  draw-off  branches. 

It  is  not  an  uncommon  thing  in  old  tenement  buildings  to 
find  a  similar  arrangement  to  that  given  in  Fig.  237.  This  is  a 
case  of  scamped  work,  and  it  often  proves  very  disagreeable 
for  the  dweller  in  the  top  flat.  It  will  be  observed  that  the 
cylinders  on  the  different  floors  are  supplied  by  one  common 
pipe,  and  although  the  branch  connections  may  be  made  as 
shown,  hot  water  is  frequently  withdrawn  from  the  upper 
cylinders  by  the  occupiers  of  the  lowest  flats.  This  condition 
readily  occurs  when  the  horizontal  pipe  AB  is  rather  long, 
and  where  the  supply  and  draw-off  pipes  are  of  equal  bore. 

When  the  arrangement  in  Fig.  237  is  considered,  it  will  be 
evident  that  the  horizontal  length  AB  is  not  capable  of 
discharging  so  large  a  volume  as  the  vertical  pipe  BC,  and 
in  consequence  there  is  a  tendency  for  a  partial  vacuum  to  be 
created  in  the  vertical  pipe,  when  water  will  he  siphoned 
from  the  cylinders  above. 

Systems  for  Large  Buildings. — When  dealing  with  large 
buildings,  the  general  design  of  a  system  for  heating  water 
will  largely  depend  upon  the  magnitude  of  the  system,  the 
height  of  the  building,  upon  the  positions  of  the  draw-off  taps, 
and  whether  steam  is  available  or  not.  The  heating  capacity 
of  range  boilers  is  of  course  limited,  and  although  they  are  very 
convenient  for  small  installations,  they  are  not  suitable  for 
heating  large  volumes  of  water. 

Steam,  when  available,  can  advantageously  be  utilised  for 
heating  large  volumes  of  water  in  a  limited  time,  but  it  is  not 
economical  to  specially  generate  it  for  this  purpose. 

Both  the  cylinder  and  cylinder-tank  systems  are 
commonly  adopted  for  large  buildings,  the  latter  system 
being  suitable  where  draw-off  taps  are  located  at  high  levels. 

Two  or  more  secondary  circuits  may  be  essential  in  a  large 


382     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

system,  and  the  boiler  should  be  located  as  centrally  as  possible 
in  order  to  keep  the  circuits  within  a  reasonable  length.     In 


^^SSSSsJSS^JS^^^^ 
FIG.  237. — Defective  arrangement  of  cold  supply  pipes  to  cylinders. 

certain  cases,  where  large  volumes  of  hot  water  are  required 
about  the  same  time  both  on  an  upper  and  a  lower  floor,  it 
may  be  desirable  to  provide  two  distinct  systems  of  supply. 


DOMESTIC    HOT    WATER    SUPPLY  383 

Separate  systems  may  also  be  essential  for  supplying  isolated 
groups  of  fittings  in  large  buildings. 

Cylinder-Tank  System. — As  the  term  implies,  this  is  a 
combination  of  the  cylinder  and  the  tank  systems,  and  it  is 
sometimes  claimed  that  the  combined  arrangement  retains  the 
principal  merits  of  both  systems  whilst  eliminating  their  draw- 
backs. This,  however,  depends  on  how  a  system  is  designed. 
The  pipes  may  be  arranged  in  various  ways,  a  good  method 
being  given  in  Fig.  238,  provided  the  pipes  are  properly  sized. 
The  cylindrical  tank  is  fixed  as  near  to  the  source  of  heat  as 
possible,  whilst  the  top  of  the  rectangular  tank  is  located  about 
level  with  the  bottom  of  the  cold  water  supply  cistern. 

In  Fig.  238  one  secondary  circuit  is  shown,  by  taking  the 
pipe  from  the  top  of  the  cylinder  and  joining  it  near  to  the 
bottom  of  the  rectangular  tank,  and  by  taking  it  from  the 
opposite  side  back  to  the  cylinder.  From  the  secondary 
circuit  the  draw-off  branches  are  taken. 

In  order  that  circulation  may  take  place  as  indicated  by 
the  darts,  the  secondary  flow  pipe  should  offer  the  least  resist- 
ance ;  in  other  words,  this  should  take  the  shortest  route  and 
contain  the  least  number  of  bends. 

When  a  draw-off  tap  is  opened  at  a  high  point,  say  at  P, 
Fig.  238,  water  is  free  to  flow  directly  from  the  overhead  tank, 
and  also  from  the  cylinder.  In  any  case  a  free  discharge  at 
P  is  assured,  whereas,  with  a  cylinder  system,  the  whole  of  the 
water  before  being  withdrawn  must  pass  to  the  cylinder  before 
it  can  escape  at  a  higher  point.  Where  pipes  are  of  consider- 
able length,  and  the  point  of  draw-off  at  a  high  level,  the 
outflow  of  water  from  a  cylinder  system  may  be  far  from 
satisfactory. 

With  regard  to  the  comparative  sizes  of  cylindrical  and 
rectangular  tanks,  that  is  a  matter  which  can  only  be  settled 
when  the  whole  circumstances  of  any  particular  case  are  taken 
into  account.  For  example,  assuming  the  larger  volume  of 
hot  water  is  required  at  a  high  level,  then,  as  a  rule,  the  upper 
tank  should  have  the  larger  capacity.  On  the  other  hand, 
where  the  greater  demand  for  hot  water  is  made  at  a  lower 
point,  the  cylinder  may  require  to  have  the  larger  capacity. 
In  each  case,  however,  the  sizes  and  general  arrangement  of 


384     DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 


the  pipes  will  require  to  be  taken  into  account.  Under 
favourable  conditions,  where  there  is  free  circulation  between 
the  cylindrical  and  the  upper  tank,  the  hottest  water  will  be 


FIG.  238. — Cylinder-tank  system. 

stored  in  the  latter ;  if,  however,  the  circulation  in  the 
secondary  circuit  is  retarded  by  long  stretches  of  nearly 
horizontal  pipe,  which  may  be  of  small  bore,  then  the  hottest 
water  will  accumulate  and  remain  in  the  lower  tank. 


DOMESTIC    HOT    WATER   SUPPLY  385 

A  by-pass  B  is  shown  in  Fig.  238  between  the  primary 
and  the  secondary  flow  pipes ;  this  may  be  an  advantage  in 
certain  cases,  as  a  portion  of  the  hottest  water  may  be  delivered 
directly  from  the  boiler  to  the  upper  tank.  When  the 
secondary  circuit  joins  the  upper  tank  in  the  manner  shown, 
the  latter  should  be  as  shallow  as  practicable,  so  as  to  limit 
the  difference  in  temperature  between  the  highest  and  lowest 
particles  of  water. 

It  may  occasionally  be  necessary  to  arrange  two  or  more 
circuits,  as  in  Fig.  239,  when  a  building  is  large  and  the  fittings 
are  somewhat  scattered.  Each  secondary  flow  may  be  separately 
joined  with  the  cylinder,  and  although  this  is  not  absolutely 
essential,  it  is  generally  desirable,  as  each  circuit  can  be 
independently  and  readily  controlled. 

Much  more  care  is  necessary  when  designing  a  cylinder- 
tank  system,  when  compared  with  a  cylinder  system,  if  good  re- 
sults are  to  be  obtained.  Suppose,  for  example,  a  large  volume 
of  water  is  withdrawn  through  branch  M,  in  the  right  hand 
circuit  of  Fig.  239,  the  greater  volume  of  water  would  flow  from 
the  lower  tank ;  in  fact,  it  is  quite  possible  when  the  general 
design  is  as  shown,  and  when  the  horizontal  distance  between 
the  upper  hot-water  tank  and  the  vertical  part  of  the  secondary 
return  is  more  or  less  considerable,  to  draw  warm  water 
through  M  when  much  hotter  water  is  stored  in  the  overhead 
tank.  The  reason  for  this,  of  course,  would  be  due  to  the  lower 
part  of  the  secondary  return  offering  much  less  resistance  to 
the  flow  of  water  to  the  point  of  escape. 

The  position  of  the  overhead  hot- water  tank  is  an  important 
factor  in  a  cylinde-rtank  system.  In  the  circuit  on  the  left 
side  of  Fig.  239  the  overhead  hot- water  tank  is  located  near  to 
the  vertical  return,  whilst  on  the  right  circuit  it  is  placed  near 
to  the  vertical  flow  pipe.  Assuming  water  is  withdrawn  at 
point  T,  the  advantage  of  a  hot-water  tank  immediately  over- 
head is  at  once  apparent,  as  the  whole  of  the  head  between 
the  point  of  draw-off  and  the  water  in  the  tank  is  available 
for  forcing  water  to  the  point  of  escape. 

A  branch  between  the  secondary  flow  and  return  on  the  top 
floor  may  in  many  cases  be  an  advantage,  as  hot  water  may  be 
directly  delivered  from  either  tank  to  points  P  and  T  in  Fig.  239. 


386      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

When,  however,  a  branch  between  a  secondary  flow  and 
return  is  provided,  care  is  necessary  in  its  arrangement  in 
order  that  the  heating  of  the  water  is  not  impaired  by  short 
circuiting  taking  place. 


FIG.  239. — Cylinder-tank  system  with  two  secondary  circuits. 


If  it  should  be  desired  to  have  hot  water  readily  available 
at  a  point  say  N,  Fig.  239,  a  branch  circuit  should  be  provided 
as  shown  by  dotted  lines  at  D.  In  this  case  the  dipping  of 
a  main  secondary  circuit  would  be  prejudicial  to  the  heating 
of  the  water  in  the  upper  tank. 


DOMESTIC    HOT    WATER    SUPPLY  387 

111  a  cylinder-tank  system  it  is  not  only  a  question  of 
whether  water  will  circulate  along  a  given  route,  but  whether 
the  circulation  will  be  sufficiently  active  to  make  a  system 
efficient. 

Another  point  of  importance  is,  that  when  a  large  volume  of 
water  is  to  be  withdrawn  at  any  one  time  from  the  secondary 
return,  the  connection  with  the  lower  tank  should  be  as  high 
as  practicable.  For  a  given  capacity  of  cylinder  the  diameter 
should  also  be  small,  in  order  that  the  tank  may  be  fairly  high. 

Boilers  for  Heating  Water. — Speaking  generally,  boilers 
for  heating  water  are  either  classed  as  ranges  or  as  inde- 
pendent boilers,  the  former  including  those  which  are  fixed  in 
open  fire-grates. 

Boilers  take  many  forms,  and  are  made  in  cast  iron, 
wrought  iron,  and  copper.  The  choice  of  a  metal,  except  for 
the  cheapest  work,  is  usually  controlled  by  the  character  of  the 
water  to  be  used. 

Soft  waters  readily  attack  iron,  forming  ferric  oxide  or  rust, 
and  as  the  latter  is  also  objectionable  on  account  of  its  impart- 
ing redness  to  the  water,  copper  boilers  should  be  adopted  in 
soft  water  districts.  On  the  other  hand,  when  water  contains 
temporary  hardness,  iron  boilers  are  very  suitable  and  have  the 
advantage  of  a  low  initial  cost. 

Water  containing  temporary  hardness  soon  deposits  a  film 
of  carbonate  of  lime  on  the  boiler  surfaces  and  thus  protects 
the  metal  beneath. 

Cast-iron  boilers,  although  largely  used  in  some  districts, 
are  not  suitable  for  range  boilers,  unless  adequate  precautions 
are  taken  to  prevent  a  possible  explosion  taking  place.  As  a 
rule,  however,  where  cast-iron  boilers  are  used  no  special 
provision  is  made  to  render  them  safe,  on  account  of  the 
additional  expense  involved. 

Fig.  240  gives  a  common  form  of  wrought-iron  range 
boiler.  These  are  frequently  shallow  and  not  more  than  about 
6  inches  deep.  From  the  toe  to  the  back  they  should  be  as 
long  as  possible,  in  order  to  expose  a  large  surface  to  the  fire 
and  to  the  heated  products  of  combustion.  The  top  surface 
of  a  boiler  is  of  little  or  no  use  for  transmitting  heat,  on 
account  of  the  soot  which  gathers  there,  and  also  to  the  slow 


388     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


FIG.  240.— Range  boiler. 


rate   at  which   heat   is   conducted   by  water  in  a  downward 

direction.     The  front  and  bottom  surface  of  a  plain  boiler  are 

the  most  important  and  absorb 
the  greatest  amount  of  heat  per 
unit  area  of  surface. 

Frequently  range  boilers  are 
arched  as  Fig.  241,  but  with 
regard  to  their  capacity  for 
transmitting  heat  they  are 
mostly  overrated.  As  a  rule, 
there  is  little  difference  between 
the  arched  and  the  plain  type 
so  far  as  their  heating  power  is 
concerned.  In  certain  ranges, 
arched  boilers  are  necessary  on 

account  of  the  limited  depth  of  the  fire-box. 

In  Fig.  242  a  block  boiler  is  shown  in  position.     It  will 

be  observed  that  the  bottom  of  the  flue  beneath  the  boiler  is 

raised  above  the  grate,  and  this  is  desirable,  as  it  prevents,  to 

a  great  extent,  the  choking  of  the  flue  with  ashes  which  are 

often  allowed  to  accumulate  on  the   grate.     For  a  boiler  to 

absorb  a   fair  amount 

of  heat  the  bottom  flue 

e,  Fig.  242,  should  not 

be  more  than  3  inches 

deep,  whilst  its  width 

should  be  proportioned 

to  the  size  of  the  fire. 

The  flue  over  the  top 

of  the  boiler  should  be 

shallow,  and,  as  a  rule, 

not    more    than    1J 

inches  deep.     The  top 

of  the  boiler,  for 

reasons    previously 

stated,  is  practically  useless  for  transmitting  heat,  but  the  top 

flue  renders  the  front  more  effective,  as  it  can  be  enveloped 

with  flame  when  a  range  is  closed. 

A  defective  method  of  fixing  a  range  boiler  is  that,  where 


FIG.  241. — Arched  range  boiler. 


DOMESTIC    HOT    WATER   SUPPLY 


389 


the  bottom  flue  is  made  level  with  the  fire-grate.  This  allows 
the  flue  to  get  readily  choked,  and  where  the  fire-grate  also 
terminates  a  short  distance  under  a  boiler,  cold  air  enters 
directly  through  the  grate  and  cools  the  products  of  combus- 
tion which  pass  beneath  the  boiler. 

When  it  is  necessary  to  join  circulating  pipes  at  the  side 
or  back  of  a  boiler,  the   point  where  the  flow  connection  is 


FIG.  242. — Illustration'showing'flues  round  boiler. 

made  should  be  raised  as  at  F,  Fig.  240,  in  order  to  prevent 
air  being  confined  above  the  water.  The  same  precaution 
holds  good  when  the  circulating  pipes  join  at  the  top  of  a 
boiler,  for  the  flow  pipe  connection  must  not  protrude  beneath 
the  uppermost  plate. 

Boot  boilers,  Figs.  243  and  244,  provide  a  greater  area  of 
heating  surface  than  the  ordinary  block  type,  and  are  often 
used  for  heating  fairly  large  volumes  of  water.  They  provide 


390     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


a  large  amount  of  indirect  or  flue  surface  when  made  as  in 
Fig.  244,  but  it  is  necessary  to  be  careful  in  considering  it, 
and  not  to  place  too  high  a  value  upon  it.  Many  kitchen 
ranges  do  not  permit  of  the  use  of  boot  boilers,  and,  generally 
speaking,  where  large  volumes  of  heated  water  are  required, 
it  is  more  economical  and  satisfactory  to  dispense  with  the 
range  boiler  and  to  substitute  a  good  type  of  independent 
boiler.  For  large  establishments  where  a  great  amount  of 
cooking  is  done,  range  boilers  are  often  a  source  of  annoyance, 
as  they  greatly  interfere  with  the  heating  of  the  ovens. 

When  a  range  boiler  is  a  fair  distance  from  front  to  back, 
and  water   which  contains   temporary  hardness   is   used,  the 

return  connection  should  be 
arranged  to  terminate  near  the 
front  or  toe  of  the  boiler,  as  in 
Fig.  242.  If  this  is  done  and 
the  flow  connection  is  located 
at  the  back,  a  better  circulation 
will  be  maintained  inside  the 
boiler,  and  less  saline  matter 
will  be  deposited  upon  the 
boiler  surfaces.  Lime  salts,  as 
a  rule,  are  not  thrown  out  of 
solution  to  any  great  extent 
before  the  water  approaches  a 
temperature  of  180°  F.,  but 

unless  the  heated  particles  of  water  are  freely  displaced  from 
the  front  of  a  boiler,  local  currents  may  be  set  up,  and  when 
a  big  fire  is  burning,  the  water  at  the  front  may  be  con- 
siderably hotter  than  that  at  the  back.  If  the  circulation  is 
restricted  within  a  boiler,  lime  salts  are  freely  deposited  owing 
to  the  high  temperatures  recorded,  whilst  a  free  displacement 
of  heated  water  tends  to  produce  a  more  nearly  uniform 
temperature  within  a  boiler.  It  is  specially  desirable,  where 
temporary  hard  water  is  used,  that  a  range  boiler  takes  a 
simple  form,  and  that  heated  water  is  not  unnecessarily  impeded 
in  passing  to  the  point  of  escape.  The  free  circulation  of  water 
within  a  boiler  is  not  a  complete  cure  for  the  deposition  of 
saline  matter,  but  it  is  a  simple  means  of  reducing  the  trouble. 


FIG.  243.— Boot  boiler. 


DOMESTIC    HOT    WATER    SUPPLY 


391 


To  remove  scale  from  boilers,  suitable  hand  holes  should 
be  provided  which  allow  access  to  every  part.  The  scale  is 
usually  thickest  where  the  heat  is  greatest,  and  this  accounts 
for  the  leakage  of  boilers  through  being  burned.  Apparatus 
may  be  arranged  for  preventing  the  deposition  of  lime  salts 
and  the  formation  of  scale ;  this  will  be  considered  later. 

The  range  boiler  given  in  Fig.  245  differs  from  those 
previously  given,  in  that  the  flame  and  heated  products  of 
combustion  take  a  course  over  the  front  edge,  down  the  centre 
flue,  and  up  the  back.  This  type  of  boiler,  on  account  of  the 


FIG.  244. — Boot  boiler  with  arched  and  centre  flue. 

descending  flue,  will  minimise  the  draught,  and  in  consequence 
will  consume  less  fuel  in  a  given  time,  when  compared  with 
one  where  the  flue  passes  directly  beneath  it  and  up  the  back. 
At  the  same  time,  the  heating  surface  of  a  boiler  like  Fig.  245 
will  absorb  less  heat  per  unit  area  than  one,  say,  like  Fig.  242. 
The  type  shown  in  Fig.  245  is  suitable  for  heating  limited 
volumes  of  water,  and  its  form  of  contruction  is  advantageous 
where  temporary  hard  water  is  used,  as  the  salts  are  pre- 
cipitated to  the  bottom,  which  is  well  below  the  level  of  the 
fire.  The  solid  matter  chiefly  falls  clear  of  the  heated  surfaces, 
and  it  can  be  removed  in  the  form  of  sludge  at  the  access 


392     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

opening  A.  It  is  of  course  essential  that  saline  matter  is 
not  allowed  to  accumulate  and  to  reach  the  level  of  the  tire, 
or  the  upper  layers  may  be  converted  into  a  hard  mass  which 


Fig.  245.  —  "  Mermaid  "  boiler  set  in  range. 

can  only  be  removed  by  the  application  of  force.     To  enable 
the  flues  to  be  cleaned,  a  soot  door  D  is  provided  in  Fig.  245. 

Independent  Boilers  take  various  forms,  and  are  made  in 
wrought  iron,  mild  steel,  cast  iron,  and  copper.  In  Fig.  246, 
a  dome-top  type  is  shown,  where  the  waterway  sides  are  carried 


DOMESTIC    HOT    WATER    SUPPLY 


393 


beneath  the  fire  bars.  This  form  of  boiler  permits  a  great 
amount  of  heat  to  escape  into  the  chimney,  but  its  efficiency 
is  increased  if  cross  tubes  are  added.  Cross  tubes  add  to  the 
initial  cost  of  a  boiler,  but  this  is  repaid  by  the  amount  of  fuel 


FIG.  246. — Independent  boiler  by  Lumby  Sons.  Wood  &  Co.  Ltd. 

saved.     Boilers  are  more  fully  considered  in  the  next  chapter, 
where  other  types  are  also  given. 

Duty  of  Range  and  Dome-Top  Independent  Boilers. — Some 
idea  of  the  heating  capacity  of  boilers  is  often  required, 
especially  when  large  volumes  of  water  require  to  be  heated 
in  a  limited  time.  The  heat  transmitted  through  a  square 
foot  of  boiler  surface  varies  considerably,  and  depends  upon 


394     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

the  form  it  takes,  and  whether  it  is  exposed  to  the  direct  heat 
of  the  fire  or  not.  Surfaces  in  direct  contact  with  fire  absorb 
considerably  more  heat  than  indirect  surfaces,  as  the  former 
receive  radiant  heat  from  the  fire,  flame  impact,  and  heated 
products  of  combustion.  On  the  other  hand,  indirect  surfaces 
(those  which  are  not  exposed  to  the  fire)  only  receive  heat 
from  the  products  of  combustion,  and  a  certain  amount  from 
flame  impact. 

In  order  to  simplify  calculations  in  connection  with  range 
boilers,  the  vertical  surfaces  which  are  only  subjected  to  the 
ascending  products  of  combustion  will  be  omitted,  as  their 
precise  value  is  difficult  to  ascertain.  Under  the  best  con- 
ditions the  value  of  indirect  surfaces  is  comparatively  small, 
but  an  average  approximate  value  for  these  surfaces  will  be 
included  in  the  data  given. 

Formulae  for  Range  Boilers. — The  following  formula  is 
applicable  to  range  boilers  for  determining  the  approximate 
volume  of  water  which  can  be  raised  in  a  given  time  from 
about  42°  to  170°  Fahr.  when  a  good  fire  is  burning: — 

G=ftxqxt (70) 

Where  G  =  gallons  of  water  raised  from  42°  to  170°  F. 

E  =  effective  heating   surface   of   boiler   in   square 

inches. 
„       q  —  a  constant  which  varies  with  the  type  of  boiler. 

(see  Table  XII). 
„        t  —  time  for  heating  water  in  hours. 

TABLE  XII. 

VALUE  OF  q  FOR  DIFFERENT  BOILERS 


For  types  similar  to  Figs.  240  and  241 
Fig.  243  .        v 
„    244   .      [-, 
,    245  . 


g-nr'076  or  ^ 
7= '083,,  ifc 


it  0 


g=-028,, 


The   effective  heating   surface  of  boilers  like  Fig.  240  to 
Fig.  244  inclusive,  is  considered  to  be  that  at  the  front  and 


DOMESTIC    HOT   WATER   SUPPLY  395 

the  bottom  and  which  is  clear  of  brick  or  other  settings.  For 
a  boiler  similar  to  Fig.  245,  the  effective  surface  is  taken  as 
the  front  S,  plus  that  of  the  centre  flue  F,  plus  the  horizontal 
surface  H,  the  lengths  of  the  latter  being  considered  equal  to 
that  of  the  centre  flue.  The  arched  flues  of  Figs.  241  and 
244  may  be  ignored,  and  the  dimensions  taken  as  for  plain 
boilers  like  Figs.  240  and  243. 

A  worked  example  or  two  will  help  to  make  the  matter 
clear. 

Example  40. — Assume  the  clear  front  of  a  boiler  (Fig.  240) 
measures  12  inches  by  6  inches  and  the  bottom  between  the 
brick  settings  8  inches  by  12  inches.  Find  how  many  gallons 
such  a  boiler  should  be  capable  of  heating  in  1J  hours. 

By  Formula  70,  G  =  E  x  <?  x  £. 

Value  of  E  =  (12  x  6)+(8  x  12)  and  in  Table  XII.  q  =  -076. 

Substituting  values  given, 


=  [(12x6)+(8xl2)lx-076x 
,     168  x  -076  x  3 

"T"    "; 

r  =  19'15,  say  19  gallons. 


Example  41. — If  a  boiler  like  Fig.  244  is  used,  and  we  desire 
its  heating  capacity  per  hour  when,  say,  a  measures  10  inches, 
b  15  inches,  c  7  inches,  and  d  14  inches. 

Formula  70  gives  G  =  E  x  q  x  t. 

E  =  (bxc)+(axd)  and  q  from  Table  XII.  =  -09. 

Substituting  values  given, 

G  =  [(15  x  7) +(10  x  14)]  x  -09  x  1. 
G  =  245x-09; 
/.  G  =  22-05,  or  say  22  gallons  per  hour. 

Example  42. — Assume  we  require  to  ascertain  the  volume  of 
water  a  boiler  like  Fig.  245  will  heat  per  hour  when  its 
principal  dimensions  are  as  follows  : — 

Front  S,  12  inches  by  7  inches.  Centre  flue,  7  inches  by 
3  inches  and  16  inches  deep.  Horizontal  surface  H,  4  inches 
wide. 

Although  the  back  is  a  little  higher  than  the  front,  for 


396     DOMESTIC    SANITARY    ENGINEERING    AND   PLUMBING 

purposes  of  calculation  this  can  be  ignored.  The  surfaces 
which  are  taken  into  account  are  —  front  of  boiler,  centre  flue, 
and  the  surface  H. 

By  Formula  70,  G  =  E  x  q  X  t. 

To  obtain  the  surface  of  the  centre  flue,  first  ascertain  its 
perimeter  and  then  multiply  by  its  depth.  Thus  the  peri- 
meter of  the  flue  given  equals  2  x  (7  +  3)  =  20  inches. 

Then  E  =  (12  x  7)  +  (20  x  16)  +  (7  x  4).  Value  of  q  from 
Table  XII.  is  given  as  -028, 

and  G  =  [(12  x  7)  +  (20  x  16)  +  (7  x  4)]  x  "028  x  1, 
G  =  432x-028; 

/.  G  =  12*09,  or  say  12  gallons  per  hour. 

If  we  wish  to  ascertain  the  approximate  time  for  heating  a 
given  volume  of  water  we  have  by  transposing  Formula  70, 


Example  43.  —  How  long  will  it  take  a  boiler  which  is  similar 
to  Fig.  241  to  raise  35  gallons  of  cold  water  to  about  170°  F.  ? 
Let  a  =  S  inches,  &  =  14  inches,  c  =  7  inches,  and  d  =  12  inches. 

By  Formula  71,*= 


Ex? 

From  Table  XI  I.  q  =  -076, 

G 


and  t  — 


35 
Substituting  values  given,  t  = 


(14x7)  +  (8xl2)x-076} 
.-.  £  =  2-37,  or  2  hours  22  minutes. 

Formulas  for  Dome-Top  Independent  Boilers. — The  method 
of  calculation  which  has  been  given  for  range  boilers  is  not 
readily  applicable  to  independent  boilers.  For  the  latter  class, 
it  is  far  better  to  determine  their  diameter  when  ascertaining 
their  size  than  to  compute  the  area  of  the  heating  surface. 
The  efficiency  of  an  independent  boiler  is  controlled  by  the 
rate  of  combustion,  by  the  arrangement  and  form  of  the  heating 
surface,  and  by  the  ratio  of  the  grate  area  to  the  heating 


DOMESTIC    HOT    WATER    SUPPLY  397 

surface.     When  a  given  rate  of  firing  is  decided  upon,  and  the 
kind  of  fuel  to  be  used,  the  formula  may  take  a  simple  form. 

The  following  formulae  for  dome-top  boilers  is  applicable 
when  the  rate  of  firing  is  approximately  10  Ib.  of  fuel  per 
sq.  foot  of  grate  per  hour,  and  when  water  is  raised  from 
42°  to  about  180°  F.  :— 

For  Coal  Fuel,  Gr  =  d**t (72) 


d 


v 


5xG 
t 


(73) 
(74) 


,72  v  /  v  K 

For  Gas  Coke  Fuel,  G  =     *   *         ....     (75) 

o& 

32xG 

•         •  •     (7b) 


32xG  (77) 

Where  G  =  gallons  of  water  heated. 
„       d  =  internal  diameter  of  boiler. 
„       t  =  approximate  time  in  hours. 

Example  44. — Determine  the  number  of  gallons  of  cold 
water  which  can  be  raised  by  an  11-inch  internal  diameter 
do  me- top  boiler  in  2J  hours  when  coal  fuel  is  used. 

Using  Formula  72,  G  =  — - — . 

II2  x  2i 

Substituting  values,  G  = 


o 
.-.  a  =  60j  gallons. 

Example  45.  —  What  should  be  the  internal  diameter  of  a 
dome-top  boiler  to  heat  75  gallons  per  hour  when  using  coal 
fuel  ? 

By  Formula  74,  d= 


Substituting  values,  d  = 


/.  d  =  19'3,  say  19  inches  diameter. 


398      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

Values  computed  by  Formulae  72  and  75  will  generally  be 
found  lower  than  those  given  in  a  manufacturer's  catalogue. 
Catalogue  values  are,  as  a  rule,  considerably  overrated,  and  the 
basis  upon  which  they  are  computed  is  often  far  from  being 
satisfactory. 

Sizes  and  Capacities  of  Hot- Water  Tanks. — The  capacity  of 
a  hot-water  storage  tank  should  be  governed  by  the  maximum 
demand  for  hot  water  in  the  minimum  time,  and  by  the  power 
of  the  boiler  or  heater. 

In  a  small  private  house  the  greatest  volume  demanded 
at  any  one  time  is  usually  for  a  bath,  and  a  tank  of 
30  gallons  capacity  usually  provides  sufficient  storage.  Tanks 
of  smaller  capacity  are  often  used  in  certain  dwellings, 
chiefly  for  economical  considerations  when  installing  an 
apparatus,  and  not  because  a  smaller  tank  possesses  any 
other  merit. 

For  large  buildings,  where  hot  water  is  freely  used,  the 
storage  capacity  requires  to  be  liberal.  Suppose,  for  example, 
that  in  half-an-hour  200  gallons  of  water  at  an  approximate 
temperature  of  104°  are  required.  Taking  the  average 
temperature  of  the  hot  water  in  the  tank  at  166°,  and  the 
temperature  of  the  cold  water  at  42°,  equal  volumes  of  cold 
and  hot  water  would  be  necessary  to  produce  the  200  gallons 
at  the  temperature  desired.  If  a  powerful  boiler  is  used,  say, 
one  which  is  capable  of  heating  100  gallons  of  cold  water  to 
about  170°  in  one  hour,  then  a  storage  capacity  of  100  gallons 
would  be  ample.  On  the  other  hand,  assuming  that  a  similar 
volume  of  water  is  required,  but  only  at  long  intervals,  a  less 
powerful  boiler  could  be  used  and  the  storage  capacity  of  the 
hot  water  tank  increased  by  30  to  50  per  cent.  The  increased 
capacity  is  to  compensate  for  the  mixing  of  the  cold  with  the 
hot  water,  when  drawing  off  water  for  a  rather  prolonged 
period.  The  margin  to  be  allowed,  however,  may  also  be 
governed  by  the  dimensions  of  a  tank.  Cylindrical  tanks 
when  vertically  placed,  if  of  a  comparatively  small  diameter, 
require  a  less  capacity  margin  than  those  of  a  larger  dia- 
meter. Horizontally  fixed  cylindrical  tanks  also  require  a 
larger  capacity  margin  than  those  which  are  vertically 
arranged. 


DOMESTIC    HOT    WATER   SUPPLY  399 

The  sizing  of  a  tank  according  to  the  number  of  draw-off 
taps  is  no  real  guide,  as  the  volume  of  water  required,  or  used, 
is  not  directly  proportional  to  the  number  of  taps. 

To  arrive  at  the  required  capacity  of  a  hot-water  tank  it 
is  better  to  first  ascertain  the  volume  of  hot  water  at  a. 
high  temperature,  which  will  produce  along  with  cold  water 
the  volume  required  at  any  given  lower  temperature.  To 
this  a  marginal  capacity  should  be  added  of  from  10  to 
50  per  cent,  according  to  the  power  of  the  proposed  boiler, 
the  diameter  of  the  tank,  and  the  position  of  the  tank  when 
fixed. 

Example  46. — Find  the  capacity  of  a  cylinder  which  will 
hold  sufficient  hot  water  at  an  average  temperature  of  160° 
F.  to  produce  150  gallons  of  water  at  120°  F. 

The  temperature  of  the  cold  water  is  44°. 

First  find  the  volume  at  160°  which  will  produce,  along 
with  cold  water,  150  gallons  at  120°. 

Let  x  =  volume  of  hot  water  at  160°,  when  150  —  x  —  volume 
of  cold  water  at  44°. 

If  P  =  temperature  of  hottest  water. 

„  T  =  temperature  of  water  desired. 

„    t  =  temperature  of  cold  water. 

Then  x  (P-T)  =  (150-»)x(T-0- 

Substituting  values  given, 

a?(160-120)=(150-aj)x(120-44> 

Simplifying  40#  =  (150  -  a?)  x  76. 
40a;=  11400 -763. 
116a=11400. 

From  which,  x—    ......    =98  -/$•  gallons. 

Therefore  the  volume  of  hot  water  at  160°  F.,  which  is 
necessary  to  produce  the  volume  required,  may  be  taken  as  98 
gallons. 

Assuming  a  few  hours  are  required  to  heat  this  volume 
of  water,  the  capacity  of  the  cylinder  may  be  increased  by  40 
per  cent,  when  the  final  capacity  =  98  +  39  =  137  gallons. 


400      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

Sizes  of  Cylindrical  Tanks.  —  From  the  following  simple 
rules  either  the  capacity  in  gallons  or  one  dimension  can  be 
obtained  when  the  remaining  particulars  are  given  :  — 


Where  G  =  capacity  in  gallons. 

„       k  =  height  or  length  of  tank  in  inches. 
„        d  =  diameter  in  inches. 

Example  47.—  Find  the  volume  of  water  a  cylindrical 
tank  will  hold  when  its  diameter  is  2  ft.  9  in.  and  its  height 
4  ft.  6  in. 

By  Formula  78,  G= 

„  ,    ...    ,.  n     33x33x54 

Substituting  values,  G-  = 


.-.  G  =  166,  say  166^  gallons. 


Example  48. — A  cylindrical  tank  of  80  gallons  capacity  has 
a  diameter  of  20  inches,  determine  its  height. 

TT   •          17  1       >7Q     7         353  XG 

Using  Formula  78,  h  =  — -^ — . 

353  x  80 

Substituting  values,  h=  9Q     2Q  ; 

.-.  h  =  7  Of  inches,  say  5  ft.  10^  in. 

Example  49. — What  diameter  of  cylinder  would  be  required 
to  hold  65  gallons  when  its  height  is  4  feet  ? 


By  Formula  80,  ^  = 

v        h 

Substituting  values,  ^=/v/353x65 ; 


48 
=  21-8  in.,  say  1  ft.  9}  in. 


DOMESTIC   HOT    WATER   SUPPLY  401 

Square  and  Rectangular  Tanks.  —  The  capacity  of  these 
tanks  or  any  dimension  can  be  obtained  when  the  remaining 
values  are  given. 

.        ......    (81) 


t_277xG 
Ixh     ' 

'-       <«> 

Where  G  =  con  tents  in  gallons. 

1  =  length  of  tank  in  inches. 
„        b  =  breadth  in  inches. 
„        h  =  height  or  depth  in  inches. 

Sizes  of  Pipes  for  Systems  of  Hot-  Water  Supply.  —  The  sizes 
of  circulating  pipes  between  a  boiler  and  a  cylinder  are  usually 
determined  by  arbitrary  rules;  the  chief  thing  is  to  provide 
a  passage  which  will  not  unduly  retard  circulation.  Where 
draw-off  branches  are  taken  from  secondary  circuits,  the  latter 
should  be  sized  to  properly  supply  the  number  of  taps  which 
are  likely  to  be  in  use  at  the  same  time. 

For  a  small  system  which  is  supplied  with  soft  water  f-inch 
circulating  pipes  are  usually  satisfactory.  If  these  pipes  are 
long  they  should  be  increased  in  size.  Larger  circulation  pipes 
are  also  desirable  when  they  require  to  be  trapped,  in  order  to 
compensate  for  a  slower  rate  of  movement  of  the  water. 

In  hard  water  districts  where  deposits  occur  in  pipes  and 
boilers,  larger  circulating  pipes  should  be  used  than  in  soft 
water  areas.  An  increase  of  one  size  is  usually  sufficient 
where  the  conditions  are  similar.  The  return  pipe,  as  a  rule,  is 
not  materially  affected  by  deposit,  the  salts  which  escape  from 
the  boiler  being  usually  precipitated  in  the  flow  pipe. 

For  large  systems  where  independent  boilers  are  used, 
the  minimum  size  of  circulating  pipes  should  be  1^  inches 
diameter. 

Generally  speaking,  feed  pipes  to  cylinders  should  not  be 
26 


402      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

less  than  one  size  larger  than  the  principal  draw-off  pipes  ;  a 
large  feed  pipe  is  specially  necessary  where  there  is  only  a 
short  vertical  distance  between  the  top  of  the  hot  water  and 
cold  supply  tanks. 

For  comparatively  small  systems  the  principal  draw-oft 
pipe  from  a  cylinder  does  not  require  to  exceed  1  inch 
diameter,  but  in  the  case  of  large  installations  where  pipes  are 
long,  their  sizes  are  better  ascertained  by  the  aid  of  hydraulic 
formula,  when  the  special  requirements  of  each  system  can  be 
taken  into  account. 

Steam  Apparatus  for  Heating  Water. — Steam,  when  avail- 
able, as  in  many  large  buildings,  is  a  very  suitable  and 
convenient  agent  for  heating  water,  and  it  possesses  the  special 
advantage  of  being  able  to  raise  large  volumes  to  a  relatively 
high  temperature  in  a  limited  time. 

Properties  of  Steam. — To  convert  water  at  2 1 2°  F.  into 
steam  at  the  same  temperature,  requires  966  B.T.U.  per  pound 
of  water.  The  British  thermal  unit  is  generally  expressed  by 
the  abbreviation  B.T.U. ,  and  represents  the  amount  of  heat 
necessary  to  raise  one  pound  of  water  from  39°  to  40°  F.  or,  say, 
through  one  degree. 

The  heat  which  is  necessary  to  convert  water  at  any 
temperature  into  steam  at  the  same  temperature,  is  known  as 
the  latent  heat  of  steam,  and  this  value  varies  according  to  the 
pressure  of  the  steam.  For  steam  at  atmospheric  pressure 
(equivalent  temperature  212°  F.  ),  its  latent  heat  is  966,  and 
for  pressures  less  than  that  of  the  atmosphere,  the  value  of 
the  latent  heat  increases.  On  the  other  hand,  when  the 
pressure  of  steam  exceeds  that  of  the  atmosphere,  its  latent 
heat  is  less  than  966  ;  in  other  words,  less  heat  is  necessary  to 
change  water  from  the  liquid  into  the  gaseous  state. 

As  the  heat  which  is  stored  in  steam  is  given  up  upon  its 
condensation,  its  value  as  a  heating  agent  is  apparent.  For 
example,  1  Ib.  of  steam  at  15  Ib.  per  sq.  inch,  (gauge  pressure) 
when  condensed  and  when  the  water  of  condensation  is  cooled 
to  150°  F.,  gives  up  939 +  (250 -150)  =  1039  B.T.U. 

The  value  939  is  obtained  from  Table  XIII.  and  is  the  latent 
heat  of  steam  for  the  pressure  given. 

From  the   same   Table,   the  value  250  will   be   found   to 


DOMESTIC    HOT    WATER   SUPPLY 


403 


represent  the  temperature  of  the  steam  when  subjected  to  a 
pressure  of  15  Ib.  per  sq.  inch. 

Boiling  Point. — The  boiling  point  of  water  is  a  variable 
quantity.  At  sea  level  water  boils  in  an  open  vessel  at  212°  F., 
but  if  it  is  subjected  to  greater  pressure  by  confining  it  in  a 
closed  vessel,  the  boiling  point  is  raised.  At  high  altitudes, 
water  in  an  open  vessel  boils  at  less  than  212°,  and  the  same 
result  is  obtained  when  water  is  confined  in  a  vessel,  and  when 
the  air  pressure  in  the  vessel  is  reduced  by  an  air  pump  or  by 
other  means. 

TABLE  XIII. 

PROPERTIES  OF  STEAM 


Pressure  in 
Ib.  per 
sq.  inch. 

Tempera- 
ture F. 

Latent 
heat. 

ITS:;'*'* 

Latent 
heat. 

Atmospheric 

212 

966 

16       252 

938 

1 

216 

963 

17       254 

936 

2 

219 

961 

18       256 

935 

3 

222 

959 

19       257 

934 

4 

225 

957 

20       259 

933 

5 

228 

955 

21        261 

931 

6 

231 

953 

22        262 

930 

7 

233 

951 

23        264 

929 

8 

235 

949 

24        266 

928 

9 

238 

948 

25        267 

927 

10 

240 

946 

26        269 

926 

11 

242 

945 

27       270 

925 

12 

244 

943 

28       272 

924 

13 

246 

942 

29       273 

923 

14 

248 

940 

30       274 

922 

15 

250 

939 

31       276 

921 

Heating  Water  by  Steam. — There  are  two  general  methods 
of  heating  water  by  means  of  steam — (a)  the  direct  method, 
where  live  steam  is  introduced  into  the  water ;  and  (b)  the 
indirect  method,  where  the  steam  and  water  are  kept  apart  by 
arranging  steam-heated  surfaces  which  are  surrounded  with 
water. 

The  direct  method  is  limited  in  its  application,  on  account 
of  the  noise  usually  caused  when  steam  and  water  come 
together,  and  the  increase  in  volume  of  the  water  due  to 


404      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

condensation  of  steam.  This  mode  of  heating  water,  however, 
is  often  suitable  for  industrial  purposes,  and  for  heating  water 
in  swimming  ponds  as  well  as  for  other  special  uses. 

For  general  work  indirect  steam  heating  is  necessary,  but 
less  heat  is  abstracted  from  a  given  weight  of  steam  than  with 
the  direct  method,  One  of  the  simplest  forms  of  indirect  steam 
heaters  is  shown  in  Fig.  247.  A  copper  coil  in  the  cylinder 
takes  the  place  of  a  boiler,  steam  being  admitted  at  the  upper 
part,  whilst  the  water  of  condensation  drains  to  a  steam  trap  T, 
which  is  located  in  any  convenient  place.  The  feed  and  draw- 


FIG.  247. — Steam  heater.     (Union  connections  omitted. ) 

off  pipes  in  connection  with  the  cylindrical  tank  are  arranged 
as  in  systems  where  boilers  are  used. 

If  the  water  of  condensation  could  be  arranged  to  gravitate 
to  the  boiler,  a  steam  trap  may  not  be  necessary,  but  where 
steam  is  taken  from  a  high-pressure  boiler,  and  its  pressure  is 
reduced  before  being  admitted  to  a  heater,  a  steam  trap  is 
imperative  unless  some  other  contrivance  is  introduced. 

The  tubes  of  steam  heaters  or  calorifiers,  as  they  are 
frequently  termed,  take  different  forms  and  they  are  arranged 
in  a  variety  of  ways.  So  far  as  the  amount  of  heat  which  is 
abstracted  from  a  given  weight  of  steam  is  concerned,  one  form 


DOMESTIC    HOT    WATER   SUPPLY 


405 


of  heater  is  as  effective  as  another.  It  is,  however,  customary 
when  comparing  steam  heaters  to  speak  of  one  form  as  being 
more  efficient  than  another  form,  and  the  term  should  not  be 
taken  to  indicate  that  one  form  of  heater  uses  less  steam  than 
another  to  do  a  specific  amount  of  work,  but  only,  that  a  par- 
ticular form  of  tube  arrangement  will  condense  more  steam 
in  unit  time  per  unit  area  than  another  form.  In  other 
words,  one  form  of  heater  will  do  work  quicker  than  another, 


FIG.  248. — Steam  heater  or  calorifier.     (Union  connections  omitted.) 

but  the  consumption   of  steam  is  practically  the  same  with 
different  types  for  the  same  work  done. 

Generally  speaking,  straight  plain  vertical  tubes  transmit 
heat  more  slowly  than  other  forms  per  unit  area,  and  the  reason 
for  this  is,  that  instead  of  the  water  of  condensation  spreading 
evenly  over  the  whole  surface  of  the  tube,  it  trickles  down 
them  in  streams,  and  leaves  a  large  area  not  wetted.  Coils 
are  therefore  largely  adopted  for  heaters,  as  the  retardation 
introduced  by  changes  of  direction  permits  of  a  greater  tube 


406      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

surface  being   wetted,   and  the  rate   of  heat  transmission   is 
consequently  increased. 

Instead  of  placing  a  coil  inside  a  tank,  as  in  Fig.  247,  the 
heater  is  often  fixed  as  an  independent  unit,  as  in  Fig.  248. 
This  is  preferable,  for  when  a  heater  requires  to  be  repaired 
it  can  be  readily  detached  from  the  tank.  In  Fig.  247  the 
tank  is  shown  with  a  removable  top,  in  order  to  render  the  coil 
accessible.  The  heater  in  Fig.  248  consists  of  a  number  of 


Washout 

FIG.  249. — James  Pyle  &  Co.'s  steam  heater  with  automatic  device  for 
controlling  steam  supply. 

tubes  which  communicate  with  steam  spaces  at  the  ends. 
Flow  and  return  pipes  are  arranged  in  the  ordinary  manner. 
A  safety  valve  may  be  necessary  at  the  top  of  the  heater, 
but  this  principally  depends  upon  the  strength  of  the  casing 
and  the  pressure  of  the  steam. 

When  coils  are  used  for  heaters,  their  length,  as  a  rule, 
should  not  greatly  exceed  150  diameters,  otherwise  their  lower 
parts  will  be  useless  for  transmitting  heat.  Thus  for  a  coil 
of  1-inch  copper  tube  its  maximum  length  should  be  about 


DOMESTIC    HOT    WATER    SUPPLY 


407 


12  feet.  Where  a  greater  length  of  tube  is  necessary  to 
transmit  the  requisite  quantity  of  heat,  two  or  more  coils  may 
be  formed. 

To  obviate  overheating,  and  to  prevent  waste  of  steam,  it 
is  essential  that  a  heater  be  provided  with  some  device  for 
automatically  controlling  the  steam  supply.  There  are  various 
means  of  accomplishing  this  end,  one  method  being  shown  in 
Fig.  249,  where  the  steam  valve  is  operated  by  a  steam  trap  T. 
To  the  inlet  A  of  the  trap  a  spindle  is  joined,  the  other  end  of 
the  spindle  being  joined  with  the  steam  valve  B.  The  trap  is 
of  the  expanding  and  contracting  type,  and  is  more  clearly 
shown  in  Fig.  251. 


5teom  Outlet 


Inlet  for  water 
of  Condensation , 


5team  Inlet 

FIG.  250. — Section  of  James  Pyle  &  Co.'s  automatic  steam  valve. 

The  automatic  valve  in  Fig.  249  is  brought  into  action 
as  follows :  So  long  as  there  remains  a  certain  difference  in 
temperature  between  the  steam  and  the  water  to  be  heated, 
the  steam  is  condensed,  and  its  discharge  effected  by  the 
opening  of  the  valve  of  the  trap.  When  the  temperature 
of  the  water  in  the  heater  is  raised,  the  valve  of  the  steam 
trap  is  gradually  closed,  and  in  turn  operates  to  close 
the  steam  valve  B.  In  this  manner  the  supply  of  steam  is 
controlled  to  suit  the  rate  of  condensation,  and  when  the 
water  has  reached  the  temperature  for  which .  the  appliance 
has  been  adjusted,  the  supply  of  steam  is  cut  off. 

Figs.  250  and  251  give  sections  of  the  automatic  steam 
valve  and  trap,  which  are  shown  in  position  in  Fig.  249. 


408      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


In  the  trap  Fig.  251  a  copper  tube  is  arranged  in  the  form 
of  a  bow,  and  when  it  is  subjected  to  increased  temperature 
the  rate  of  expansion  tends  to  straighten  the  tube  and  to 
close  the  inlet  valve.  Upon  the  tube  cooling,  contraction  takes 
place,  and  the  bow  regains  its  normal  position  when  the 
valve  is  again  opened.  In  order  to  make  this  form  of  trap 
sensitive  to  changes  of  temperature,  the  copper  tube  is  some- 
times charged  with  a  volatile  liquid. 

Steam  Traps  take  many  forms,  and  their  use  becomes 
necessary  in  steam  heating  work,  where  the  water  of  con- 
densation cannot  be  returned  directly  to  the  boiler.  The 
primary  purpose  of  a  steam  trap  is  to  deal  with  the  water 


Inlch 


Adjusting  5crtfur. 


J5  Ootleh 


FIG.  251. — Section  of  steam  trap  which  is  used  in  conjunction  with 
valve  shown  in  Fig.  250. 

of  condensation,  and  to  avoid  unnecessary  waste  of  steam.  As 
a  rule  the  most  effective  form  of  steam  trap  is  the  box  type, 
and  when  circumstances  will  permit  of  its  use  it  should  be 
adopted.  The  initial  cost  of  the  box  type  may  be  higher  than 
other  forms,  but  it  is  by  far  the  cheapest  in  the  end. 

Fig.  252  gives  a  very  good  form  of  box  trap,  by  Lancaster 
and  Tonge,  where  the  opening  and  closing  of  valve  S  is  accom- 
plished by  a  quick  screw  motion  when  the  float  E  falls  and  rises. 
To  the  top  of  the  float  an  adjustable  air-valve  N  is  attached, 
to  which  is  joined  a  tube,  which  terminates  near  the  bottom 
of  the  float.  The  small  orifice  in  the  upper  part  of  the  tube 
is  to  admit  of  the  escape  of  air,  which  would  otherwise  be 
confined  in  the  float  and  interfere  with  the  working  of  the 


DOMESTIC    HOT   WATER    SUPPLY 


409 


trap.  To  start  the  trap,  water  is  poured  into  it  after  the 
cover  is  removed,  until  the  overflow  or  outlet  is  reached.  As 
water  enters  the  float  through  the  aperture  F,  it  begins  to  sink 
and  to  open  the  valve,  when  the  water  of  condensation  can  be 
discharged.  So  long  as  water  only  flows  into  the  trap,  the  ball 


Fie.  252.  — Lancaster  and  Tonge's  steam  trap. 

will  remain  submerged,  but  when  steani  reaches  and  enters 
the  float,  the  water  is  displaced  at  N  and  through  the  small 
aperture  F  in  the  float,  until  the  latter  is  rendered  buoyant  and 
the  valve  S  is  closed.  After  a  short  time  the  steam  in  the 
float  is  condensed,  and  water  again  enters  until  its  buoyancy 
is  destroyed.  If,  in  the  interval,  water  has  accumulated  at 


410      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

the   valve,  it    is    immediately   discharged,   but   when   steam 
appears  the  float  is  again  raised  and  the  valve  S  closed. 

Heat  transmitted  by  Steam  Heated  Coils  when  surrounded 
with  Water. — The  amount  of  heat  transmitted  through  tubes 
is  governed  by  the  temperature  or  pressure  of  the  steam,  by 
the  initial  temperature  of  the  water  to  be  heated,  by  the  form 
the  tube  takes,  and  whether  the  whole  of  the  heating  surface 
is  effective  or  not. 

As  regards  the  pressure  of  steam,  the  higher  it  is  the 
greater  is  the  difference  between  the  temperature  of  the 
heating  medium  and  that  of  the  water  to  be  heated,  and 
consequently  the  quicker  the  rate  of  heat  transmission.  When 
water  is  being  heated  in  a  calorifier  with  steam,  the  rise  of 
temperature  will  not  be  at  a  uniform  rate,  but  quickest  at  the 
commencement  when  the  water  is  cold. 

If,  for  example,  we  assume  that  a  volume  of  water  requires 
to  be  raised  from  44°  to  180°  with  steam  at  15  Ib.  pressure 
per  sq.  inch  (equivalent  temperature  250°  F.),  the  difference 
in  temperature  between  the  steam  and  the  cold  water  is 
250  —  44  =  206°,  and  the  difference  between  the  steam  and  the 
hottest  water  250-180  =  70°.  As  the  maximum  difference 
of  temperature  coincides  with  the  maximum  rate  of  heat 
transmission  when  other  conditions  are  equal,  it  is  obvious 
that  as  the  temperature  of  the  water  is  raised  the  rate  of  heat 
transmission  will  accordingly  be  reduced,  and  for  the  case 
given  will  be  at  a  minimum  when  the  temperature  of  the 
water  is  180°. 

For  purposes  of  calculation  it  is  usual  to  take  the  average 
difference  of  temperature  in  order  to  simplify  matters,  and 
although  this  may  not  give  results  which  are  strictly  correct 
they  are  usually  sufficiently  accurate  for  ordinary  work.  Thus 
where  the  temperature  of  the  steam  is  250°,  and  that  of  the 
cold  and  hottest  water  44°  and  180°  F.  respectively,  the  average- 
difference  of  temperature'  for  the  steam  and  water  will  be 

250-1^=138°. 

2 

The  following  Table  gives  the  approximate  number  of  heat 
units  which  are  transmitted  per  minute  per  square  foot  of  sur- 
face per  degree  difference  of  average  temperature  for  short  coils. 


DOMESTIC    HOT    WATER   SUPPLY  411 

TABLE  XIV. 


Heat  transmitted  in  B.T.U.  per 

Steam  pressure  per  square  inch.  minute  per  sq.  foot  of  surface  per 

degree  difference  of  temperature. 


5  Ib.  (temp.  228°) 
15  „  (temp.  250°) 
30  „  (temp.  274°) 


4-5 


The  above  values  are  for  an  initial  temperature  of  44°  and 
a  maximum  temperature  of  about  180°.  By  the  aid  of  the 
following  formulae  calculations  in  connection  with  steam 
heaters  may  be  made  :  — 


/-,  .  .        .    (85) 


G=vP-  Vsk^r  ~-  ••••••-•  <86> 

38xGx(T-0 
m  — 


Where  G  =  gallons  of  water  heated. 

T  =  temperature  of  hottest  water. 
t  =  temperature  of  cold  water. 
„       P  =  temperature  of  steam. 

U  =  B.T.U.  transmitted  per  minute  from  Table  XIV. 
d  =  external  diameter  of  tube  in  inches. 
/  =  length  of  tube  in  feet. 
m  =  time  in  minutes  heating  water. 

Example  50. — Determine  the  length  of  coil  when  formed  of 
1-inch  copper  tube  which  will  raise  130  gallons  of  water  in 
20  minutes  from  42°  to  180*  F.  Assume  the  steam  is  supplied 
at  15  Ib.  per  sq.  inch. 

38xGx(T-0 
By  Formula  80, 1=  , — T\TT\" 


412      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

In  Table  XIV.  the  values  of  P  and  U  are  given  as  250°  and 
6  respectively. 

Q  ,    ...   f.          ,  j  38  x  130  x  (180-42) 

Substituting  values  given,  I  = 


7_38x  130x138 
:   139x6x20    ' 

/.  Z  =  40HJ-  ft.,  say  40  ft.  10  in. 

Example  51.  —  If  a  steam  heater  contains  a  coil  of  1-inch 
copper  tube  which  is  10  feet  long,  how  many  gallons  of  water 
would  it  raise  per  hour  from  44°  to  180°  F.  when  supplied  with 
steam  at  30  Ib.  gauge  pressure  ? 


Using  Formula  86,  G  ' 

Values   of   P   and  U   from  Table  XIV.  are  274°  and  8 
respectively. 

Substituting  values  given, 


x  8x60x1x10 
\  / 

a  =  \ 1 

38  x  (180 -44) 

162x8x60x10 
38x136 

.-.  G=150jf$,  or  say  150  gallons. 

Example  52. — Ascertain  how  many  minutes  it  will  take  a 
calorifier  to  raise  350  gallons  from  42°  to  178°  F.  when  the 
total  length  of  the  1-inch  copper  coils  is  50  feet  and  when  the 
steam  pressure  is  30  Ib.  per  sq.  inch. 

38xGx(T-/) 


P--~YxUxdx/ 
2  / 

Substituting  values  given, 

38  x  350  x  (178  -42) 


DOMESTIC    UOT    WATER  SUPPLY  413 

38x350x136 

fftl  — -  .._    * 

164x8x50   ' 

.-.  m  =  27|4,  or  say  27 1-  minutes. 

As  the  arrangement  of  heating  surface  in  calorifiers  is  a 
very  important  factor  as  regards  the  rate  of  heat  transmission, 
it  is  necessary  that  experiments  be  carried  out,  in  order  to 
ascertain  the  actual  value  of  U,  for  any  special  form  of 
heater. 

Indirect  Systems  of  Hot  Water  Heating. — The  systems  to 
be  dealt  with  in  this  case  are  confined  to  those  where  hot 
water  is  the  indirect  heating  medium,  and  where  range  or 
independent  boilers  form  the  direct  or  primary  heaters. 
Indirect  heaters  of  this  type  are  only  suitable  for  waters 
which  cause  incrustation  difficulties,  as  they  are  much  more 
expensive  to  instal  and  much  slower  in  action  than  direct 
heaters. 

It  has  been  previously  stated  that  the  deposition  of  lime 
salts  from  temporary  hard  water  chiefly  takes  place  when  water 
has  its  temperature  raised  to  over  180°  F.  An  indirect  system 
is  therefore  designed  that  the  water  which  is  withdrawn  from 
it  will  not  readily  have  its  temperature  raised  to  180°  F.  The 
amount  of  solid  matter  which  is  precipitated  from  water  will 
depend  upon  the  nature  and  amount  of  hardness  the  water 
contains,  upon  the  temperature  to  which  the  water  is  raised, 
and  upon  the  volume  used. 

For  example,  supposing  that  500  gallons  of  hot  water  are 
required  in  an  establishment  per  day,  that  the  water  contains 
15  degrees  of  hardness,  and  that  when  raised  to  212°  F.  10 
degrees  of  hardness  are  eliminated.  Of  course  it  is  not  likely 
that  the  whole  of  this  volume  under  usual  conditions  would  be 
raised  to  anything  like  212°,  and  for  our  case  we  will  assume 
that  only  20  per  cent,  or  100  gallons  reaches  that  temperature. 
Upon  this  basis  the  amount  of  solid  matter  precipitated  in  a 
period  of  three  months  (91  days)  would  be  100x10x91 
=  91,000  grains,  or  13  Ib.  It  is  therefore  obvious  that,  unless 
some  measures  are  adopted  to  prevent  the  deposition  of  lime 
salts,  a  boiler  may  rapidly  be  destroyed. 

Fig.  253  gives  an  indirect  system  for  heating  water,  where 


414      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

B  represents  an  independent  boiler,  H  the  indirect  heater,  C 
the  outer  cylindrical  tank  from  which  water  is  withdrawn  at 
the  various  taps.  A  small  tank  T  supplies  the  boiler  and 


Secondary     Return. 


FIG. [253. — Indirect  heating[system. 


indirect  heater  with  water.  It  will  be  observed  that  no  water 
is  withdrawn  from  the  indirect  heater,  the  same  water  being 
heated  over  and  over  again,  and  any  loss  is  made  good  by 


DOMESTIC   HOT    WATER    SUPPLY  415 

means  of  the  small  supply  tank  T.  From  the  top  of  H  an  air- 
pipe  is  taken  and  terminates  as  shown,  the  small  tank  serving 
the  purpose  of  an  expansion  as  well  as  a  supply  tank.  It  is 
only  necessary  for  the  bottom  of  tank  T  to  be  just  above,  or  on 
the  same  level  as,  the  top  of  the  indirect  heater,  for  the  less  the 
head  the  smaller  will  be  the  maximum  temperature  to  which 
water  in  the  indirect  heater  can  be  raised. 

In  an  open  vessel  water  at  sea  level  boils  at  212°,  but  when 
a  boiler  or  indirect  heater  is  subjected  to  pressure  the  boiling 
point  of  water  is  increased.  For  example,  suppose  the  vertical 
distance  between  the  top  of  the  indirect  heater  and  the  level  of 
the  water  in  the  supply  tank  T,  Fig.  253,  is  8  inches,  the 
boiling  point  would  be  approximately  213°.  Should,  however, 
the  vertical  distance  between  the  supply  tank  and  the  boiler 
in  an  ordinary  system  be  35  feet,  the  boiling  point  at  the 
lowest  level  would  be  raised  to  250°.  The  further  application 
of  heat  when  the  boiling  point  is  reached  does  not  increase  the 
temperature  of  the  water,  but  the  latter  is  converted  into 
steam  at  the  same  temperature. 

It  will  thus  be  clear  that,  in  a  system  like  Fig.  253,  the 
water  in  the  indirect  heater  H  can  never  get  much  hotter  than 
212°  F. ;  moreover,  as  a  difference  of  temperature  must  exist 
between  the  water  in  the  indirect  heater  and  that  in  the 
cylinder  C  before  heat  can  be  transmitted  from  the  former  to  the 
latter,  the  maximum  temperature  in  C  will  be  less  than  212°. 
As  a  rule  the  water  in  the  outer  cylinder  will  not  greatly 
exceed  170°  F. 

By  arranging  the  indirect  heater  as  in  Fig.  253,  the  flow 
and  return  connections  can  be  conveniently  made  at  the  bottom 
of  the  cylinder.  Where  an  independent  boiler  is  used,  one 
with  a  water  passage  beneath  the  fire  bars  is  preferable, 
although  little  solid  matter  can  be  deposited,  owing  to  the 
water  being  seldom  renewed.  The  cold  supply  pipe  from  an 
overhead  cistern,  and  the  secondary  returns,  are  arranged  as 
in  other  systems. 

The  following  table  gives  the  temperature  at  which  water 
boils  when  subjected  to  varying  heads  ; — 


416      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


TABLE  XV. 


Head  of 
water. 

Boiling 
tempera- 
ture F. 

Head  of 
water. 

Boiling 
tempera- 
ture F. 

Head  of 
water. 

Boiling 
tempera- 
ture F. 

0  ft.    8  in. 

213 

23  ft.     9  in. 

240 

46  ft   10  in 

259 

3 

0 

216 

26 

1 

242 

49 

2 

261 

5 

3 

219 

28 

5 

244 

51 

6 

262 

7 

7 

222 

30 

9 

246 

53 

10 

264 

9 

11 

225 

33 

0 

248 

56 

1 

266 

12 

3 

228 

35 

4 

250 

58 

5 

267 

14 

6 

230 

37 

8 

252 

60 

9 

269 

16 

10 

233 

39 

11 

254 

80 

10 

281 

19 

2 

235 

42 

3 

256 

103 

11 

292 

21 

6 

238 

44 

7 

257 

128 

2 

303 

It  is  important  that  an  indirect  heater  contains  sufficient 
surface   to  dissipate  the  heat  as  quickly  as  received.    If  we 

assume  when  heating  the  water 
in  a  system  that  the  area  of  the 
indirect  heater  is  equal  to  the 
boiler  surface,  the  former  would 
readily  impart  to  the  cold  water 
surrounding  it  all  the  heat  the 
boiler  could  transmit.  When, 
however,  the  temperature  of  the 
water  in  the  indirect  heater  and 
that  surrounding  it  do  not  differ 
much,  the  area  of  the  indirect 
heater  may  be  too  small,  and 
unless  the  fire  were  checked  the 
water  may  soon  boil  in  the 
heater.  As  a  rule  the  surface 
of  an  indirect  heater  should  be 
from  3  to  4J  times  the  area 
of  the  direct  heating  surface  of 
the  boiler,  the  smaller  value 

being  adequate  for   boilers  with  controlled  draught,  and  the 
larger  value  for  boilers  without  automatic  control. 

To   increase  the    surface   of    an   indirect   heater   without 


FIG.  254. — Indirect  heater. 


DOMESTIC    HOT   WATER    SUPPLY 


417 


increasing  its  capacity,  cross  tubes  may  be  inserted  as  in 
Fig.  254.  This  would  increase  the  initial  cost  of  the  indirect 
heater,  but  a  saving  would  be  effected  on  the  size  of  the 
external  cylindrical  tank. 

Fig.    255   gives   a   section   of    the   "  Sylphon    Automatic 
Temperature  Regulator  "  for  hot-water  boilers,  by  the  National 


Leuer 


FIG.  255. — "  Sylphon  "  automatic  temperature  regulator  by 
National  Radiator  Co.  Ltd. 

Radiator  Company  Ltd.,  and  Fig.  256  shows  the  appliance  in 
position.  The  regulator  consists  principally  of  a  metal  bellows 
B,  and  a  lower  sealed  vessel  R  which  is  joined  to  the  bellows  by 
means  of  a  central  tube  T.  The  bellows  is  fully  charged,  whilst 
the  vessel  beneath  is  partially  charged  with  a  fluid  which  is 
volatilised  at  a  comparatively  low  temperature,  and  this  supplies 
the  energy  for  operating  the  appliance.  When  a  certain  tem- 
27 


418      DOMESTIC   SANITARY    ENGINEERING    AND   PLUMBING 

perature  is  reached  the  confined  liquid  is  converted  into  the 
gaseous  state,  when  the  internal  pressure  expands  the  bellows  B, 
and  imparts  motion  to  the  weighted  lever  on  the  top  of  the 
appliance.  To  one  end  of  the  lever  arm  a  chain  may  be  joined 
as  in  Fig.  256,  when  upon  the  expansion  of  the  bellows  the 
draught  damper  is  closed  whilst  the  check  damper  in  the  flue 
is  opened.  Under  these  conditions  the  draught  is  checked,  for 
the  air  supply  to  the  fire  is  diminished,  and,  simultaneously 
with  this,  air  is  admitted  into  the  flue  by  the  opening  of  the  check 


Check 
Darner. 


^..J-  Draught  Damper 


FIG.  256. — Automatic  regulator  attached  to  boiler. 

damper.  When  the  vapour  reassumes  its  liquid  state,  owing 
to  a  cooling  action  having  taken  place,  the  bellows  contracts  and 
the  position  of  the  dampers  is  reversed.  In  this  manner  the 
rate  of  combustion  is  automatically  adjusted  to  suit  the  demand 
made  upon  the  system.  By  shifting  the  weight  on  the  lever 
the  temperature  at  which  the  regulator  can  be  brought  into 
action  is  said  to  vary  from  90  to  190°. 

Collapse  of  Copper  Cylinders. — Hot-water  cylinders  collapse 
when  the  metal  of  which  they  are  made  is  not  sufficiently  rigid 
to  withstand  a  reduced  internal  pressure,  and  although  cylinders 


DOMESTIC   HOT   WATER   SUPPLY 


419 


collapse  under  different  conditions,  the  real  cause  is  the  same 
in  each  particular  case. 

A  very  common  cause  of  cylinder  collapse  is  due  to  the  air 
or  expansion  pipe  being  trapped,  so  that  the  free  escape  of  air 
from  the  system  is  prevented.  Fig.  257  will  aid  in  making 


c 


A 


FIG.  257. — Illustration  showing  how  a  cylinder  may  be  collapsed. 

this  clear.  Supposing  an  expansion  or  air-pipe  is  fixed 
immediately  beneath  a  ceiling,  as  in  the  figure  shown,  it  is 
quite  possible  for  this  pipe  not  to  rise  for  the  whole  of  its 
length.  Should  the  pipe  be  of  lead  and  be  supported  with 
hooks  or  clips,  after  a  time  it  will  sag  between  the  points  of 
support,  or,  when  the  pipe  passes  through  a  ceiling  to  a  floor 


420      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

above,  the  vertical  part  may  slip  down  a  little,  and  produce  a 
sag  as  at  A,  Fig.  257.  In  either  case  the  air  given  out  when 
heating  the  water  would  lodge  in  the  air-pipe.  Should  water 
be  withdrawn,  the  accumulated  air  would  be  relieved,  and 
pass  along  with  the  water  to  the  point  of  escape.  If,  how- 
ever, the  water  in  the  cylinder  is  heated,  and  none  is  with- 
drawn, the  air  accumulates  in  the  horizontal  pipe.  Should 
overheating  take  place,  steam  also  gathers  at  the  highest  point, 
when  water  is  gradually  forced  from  the  cylinder  back  through 
the  feed-pipe  to  make  room  for  the  steam.  The  reason  why 
the  steam  and  air  cannot  escape  through  the  air -pipe  is 
rendered  clear  when  one  considers  that  before  air  can  be 
dislodged  the  water  in  front  of  it  must  be  first  displaced 
through  the  dip  at  A,  Fig.  257.  As  the  displacement  of  the 
water  must  raise  the  column  in  C,  the  pressure  due  to  the 
latter  would  exceed  that  due  to  the  head  of  water  in  the 
supply  cistern.  The  least  line  of  resistance  under  these 
conditions  is  offered  by  the  supply  pipe,  and  through  that  pipe, 
either  part  or  nearly  the  whole  contents  of  the  cylinder  may 
be  dislodged,  provided  the  generation  of  steam  continues.  So 
long  as  the  steam  pressure  is  maintained  inside  the  tank 
nothing  serious  happens,  but  when  the  system  begins  to  cool 
condensation  of  the  steam  takes  place,  when  a  partial  vacuum 
is  produced.  If  the  cylinder  at  this  period  is  unable  to  resist 
the  atmospheric  pressure,  the  sides  give  way  and  a  collapse  is 
the  result. 

Another  way  in  which  a  cylinder  may  collapse  is  when  the 
feed  and  expansion  pipes  are  blocked  with  ice,  and  an  attempt 
is  made  to  withdraw  the  water  by  opening  the  sludge  or 
emptying  cock.  In  a  similar  manner  the  upper  cylinders  in 
connection  with  tenement  buildings,  when  treated  as  in  Fig. 
237,  occasionally  collapse.  For  example,  if  the  water  in  the 
supply  pipe  to  the  cylinders  is  frozen  near  the  cistern,  and  the 
upper  part  of  the  air-pipes  are  also  blocked  with  ice,  the  open- 
ing of  a  draw-off  tap  at  a  low  level  would  cause  water  to 
be  removed  from  the  upper  cylinders,  when  the  latter  would 
collapse. 

The  most  common  cause  of  cylinder  collapse  is  probably 
due  to  expansion  pipes  getting  locked  with  air. 


DOMESTIC    HOT    WATER    SUPPLY  421 

Prevention  of  Collapse. — When  the  cause  is  known  it  is  a 
simple  matter  to  guard  against  a  cylinder  being  collapsed.  In 
the  first  place,  a  collapse  can  only  be  brought  about  when  the 
external  pressure  overcomes  that  inside,  and  to  obviate  this  the 
air  or  expansion  pipes  should  be  arranged  and  sized,  that  air 
can  freely  enter  or  escape  from  them.  If  pipes  are  in  exposed 
positions,  they  should  be  protected  from  frost  by  well  covering 
them  with  hair  felt  or  other  suitable  material. 

A  Float  Valve  may  be  fixed  at  the  top  of  a  cylindrical 
tank  to  prevent  collapse,  but  as  a  rule  it  is  not  necessary. 
These  valves  are  arranged  to  open  and  to  admit  air  as  soon  as 
the  water  level  inside  the  tanks  begins  to  fall,  but  they  close  as 
the  water  level  is  raised. 

Vacuum  valves  are  also  used  for  the  same  purpose ;  these 
are  intended  to  open  and  to  admit  air  should  there  be  a 
tendency  for  a  partial  vacuum  to  be  formed.  The  value  of  the 
latter  class  is  doubtful,  for  should  they  stick  a  little  at  a 
critical  time  a  sufficiently  reduced  pressure  may  occur  to 
bring  about  a  collapse. 

Noises  in  Boilers. — These  are  generally  produced  by — 
(a)  Boilers  which  confine  air  at  their  upper  parts. 
(&)  Overheating  of  the  water. 
(c)  Partially  choked  circulating  pipes. 
In  the  first  case,  when  air  is  trapped  inside  a  boiler,  during 
the  heating  of  water,  a  volume  of  air  escapes,  and  produces  a 
rumbling  sound  as  it  rises  through  the  water  to  the  outlet. 
The  air  of  course  is  replenished  through  the  renewal  of  the 
water. 

In  the  second  case,  the  noises  produced  are  similar  to  the 
above,  only  that  they  may  be  more  pronounced.  When  water 
is  overheated  due  to  local  circuits  occurring  within  a  boiler, 
steam  is  generated  as  this  water  rises  and  reaches  a  higher 
level  owiug  to  its  being  subjected  to  a  lower  pressure.  Over- 
heating, as  already  stated,  is  chiefly  the  result  of  retarded 
circulations,  or  it  may  be  caused  by  a  too  powerful  boiler 
being  used. 

Partially  choked  circulating  pipes  often  produce  thumping 
sounds.  It  is  seldom  that  a  flow-pipe  is  totally  blocked  with 
lime  deposits,  although  its  bore  may  be  reduced  in  some  cases 


422      DOMESTIC   SANITARY    ENGINEERING    AND   PLUMBING 


to  one-third  its  original  size.  The  return  pipe,  as  a  rule,  is  not 
affected  to  any  great  extent  with  deposited  matter.  When 
a  flow-pipe  is  totally  or  partially  choked,  very  violent  thuds 
may  be  produced,  although  an  explosion  would  not  occur  so 
long  as  the  boiler  return  remained  clear.  The  boiler,  of  course, 
is  subject  to  damage  by  being  burned,  and  by  being  subjected 

to  considerable  strain. 

Boiler  Explosions. — 
The  most  common  cause  of 
boiler  explosion  in  connec- 
tion with  hot -water  ap- 
paratus is  due  to  pipes  being 
choked  with  ice.  Stop-cocks 
in  circulating  pipes  are  oc- 
casionally responsible  for  it 
where  safety  valves  have 
not  been  provided.  It  is 
also  possible,  under  favour- 
able conditions,  for  an  ex- 
plosion to  be  caused  by  cold 
water  gaining  admission  to 
a  boiler  when  the  latter  has 
been  deprived  of  water  and 
when  heated  to  redness. 
From  experiments  it  has 
been  found  that  so  long  as 
the  pressure  due  to  the 
sudden  generation  of  steam 
can  be  relieved  through  the 
supply  pipe  (assuming  all 

other  passages  to  be  choked),  an  explosion  will  not  take 
place.  On  the  other  hand,  when  the  feed-pipe  will  not 
afford  the  necessary  relief,  owing  to  a  screw-down  stop  tap 
acting  as  a  non-return  valve,  the  pressure  due  to  the  sudden 
generation  of  steam  may  cause  the  boiler  to  explode.  The 
latter  cause  may  be  rare,  but  the  possibility  exists  under  the 
conditions  named. 

Safety  Valves. — The  question  is  often  asked,  should  boilers 
in  connection  with  hot  water  supplies  be  provided  with  safety 


FIG.  258. — Dead- weight  safety  valve. 


DOMESTIC    HOT   WATER   SUPPLY  423 

valves  ?  No  doubt  they  should  be  used  where  they  are  some- 
times absent,  but  in  many  cases  safety  valves  can  be  safely 
dispensed  with.  For  example,  when  either  wrought  iron  or 
copper  boilers  are  used,  and  where  no  trouble  is  caused  by  the 
deposition  of  lime  salts,  and  provided  boilers  and  pipes  are 
arranged  on  inside  walls,  well  away  from  the  influence  of  frost, 
then  under  these  conditions  safety  valves  are  not  of  much 
importance.  Where,  however,  pipes  are  not  properly  protected, 
or  where  there  is  danger  of  them  getting  blocked  with  ice,  or 
choked  in  any  other  manner,  safety  valves  should  be  used. 
When  cast-iron  boilers  are  adopted,  safety  valves  should  be 
used,  and  in  this  case  their  use  should  be  made  compulsory, 
for  the  explosion  of  a  cast-iron  boiler  may  be  attended  with 
disastrous  consequences. 

With  regard  to  the  position  in  which  safety  valves  should 
be  placed,  no  hard-and-fast  line  need  be  laid  down,  and  each 
case  should  be  treated  upon  its  own  merits.  Where  stoppages 
are  not  likely  to  occur  in  the  primary  circulating  pipes,  a 
safety  valve  may  be  fixed  in  any  convenient  place,  either  at 
the  boiler  or  on  one  of  the  circulating  pipes. 

From  a  general  standpoint  a  safety  valve  should  be  fixed 
directly  on  a  boiler.  This,  however,  is  not  always  practicable, 
especially  with  range  boilers,  and  in  many  cases  it  is  either 
necessary  to  fix  a  separate  pipe  to  the  boiler  for  receiving  the 
safety  valve,  or  to  fix  the  latter  to  one  of  kthe  circulating  pipes. 
Where  trouble  is  caused  by  saline  matter  being  deposited  from 
water,  a  safety  valve  may,  with  advantage,  be  joined  with  a 
return  circulating  pipe,  and  as  near  to  the  boiler  as  possible. 
The  latter  position,  under  the  conditions  given,  is  the  least 
likely  to  be  affected  by  deposit,  and  if  fixed  directly  to  the  top 
of  the  boiler  there  is  the  possibility  of  its  being  rendered 
useless.  In  the  case  of  boot  boilers,  where  soft  water  is  used, 
safety  valves  may  be  fixed  directly  to  the  boiler,  but  when 
they  are  fixed  in  flues  they  require  to  be  protected  with  a 
suitable  form  of  loose  cover. 

A  safety  valve,  as  a  rule,  should  not  be  fixed  on  the  top  of  a 
range,  for  in  such  a  place  it  is  liable  to  be  knocked,  and  caused 
to  leak. 

Safety  valves  for  boilers  take  various  forms.     The  dead- 


424     DOMESTIC   SANITARY    ENGINEERING   AND   PLUMBING 


weight  type,  Fig.  258,  is  commonly  employed,  and  it  is  simply 
constructed,  the  valve  orifice  being  covered  with  a  metal  plug 
which  is  screwed  to  the  top  of  the  outer  casing;  over  the 
latter  loose  weights  are  placed,  the  load  being  governed  by  the 
pressure  at  which  the  valve  is  to  come  into  action. 

Another  type  of  dead-weight  valve  (Jeffrey's  patent)  is 
shown  in  Fig.  259.  This  form  of  construction  is  intended  to 
make  the  valve  less  liable  to  leakage  if  it  should  be  given 
an  accidental  knock,  or  be  jarred  in  any  way.  Instead  of 


VULCANITE 

RUBBER 

WASHER. 


FIG.  259. — Jeffrey's  dead-weight 
safety  valve. 


5oFT 
CAP. 


\ 


.WASHER 


FIG.  260.— Croydon  relief 
valve. 


using  a  hard  metal  to  metal  facing,  as  in  Fig.  258,  the  valve 
seating  is  covered  by  a  vulcanite  rubber  washer  in  a  cast-iron 
cap,  the  latter  in  turn  being  pressed  upon  by  a  rubber 
pad  which  is  inserted  in  the  upper  casing  of  the  valve.  It 
will  be  observed  that  the  upper  part  of  the  valve  is  hollow, 
and  by  introducing  lead  of  shot  the  safety  valve  may  be 
loaded  to  any  reasonable  extent.  "When  fixed,  this  valve 
should  not  be  subjected  to  the  heated  products  of  combustion, 
otherwise  the  rubber  pad  may  be  soon  destroyed  and  the  valve 
caused  to  leak. 


DOMESTIC   HOT   WATER   SUPPLY 


425 


Fig.  260  gives  a  different  type  of  valve  to  either  of  the 
above.  In  this  case,  relief  is  brought  about  when  the  soft 
metal  cap  gives  way.  Another  valve  which  is  similar  in 
principle  has  a  thin  mica  disc  in  lieu  of  the  metal  cap.  Such 


FIG.  261. — Macintosh's  mercury  gauge  and  relief. 

valves,  however,  cannot  be  adjusted  with  the  same  precision 
as  the  dead-weight  type. 

Spring  safety  valves  are  also  largely  used,  the  spring  being 
either  in  a  state  of  tension  or  compression.  Generally 
speaking  they  are  not  so  suitable  for  kitchen  boilers  as  the 
dead-weight  type. 


426     DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

An  arrangement  which  can  be  used  in  many  cases,  and 
which  is  less  likely  to  get  out  of  order  than  any  form  of  valve, 
is  the  mercury  gauge  and  relief  (Macintosh's  patent),  Fig. 
261.  The  glass  tube  T  contains  mercury,  the  pressure 
of  which  must  exceed  the  normal  pressure  of  water  in  the 
apparatus.  This  arrangement  is  intended  to  be  joined  with  a 
flow-pipe  F,  and  should  the  mercury  be  subjected  to  increased 
pressure,  the  necessary  relief  is  afforded  by  the  mercury  being 
dislodged  from  the  tube  into  the  receiver  E.  To  charge  the 
tube  with  mercury  the  plug  P  is  removed  at  the  top  of  the 
gauge. 

The  chief  drawback  to  this  type  of  gauge  is  its  cost. 
Neither  would  it  be  suitable  for  fixing  on  circulating  pipes, 
which  are  likely  to  get  choked  between  the  boiler  and  the 
point  where  it  is  introduced. 


CHAPTEE  XIV 
LOW  PRESSURE  HOT-WATER  HEATING  APPARATUS 

IN  the  British  Isles,  where  provision  is  made  for  warming 
buildings  other  than  that  by  open  fires,  low  pressure  hot-water 
apparatus  is  frequently  installed.  For  general  residence  and 
horticultural  work  this  mode  of  heating  has  much  in  its 
favour,  as  the  temperature  of  the  heating  surfaces  can  be 
regulated  to  suit  different  requirements,  and  a  mild  and  humid 
atmosphere  can  be  maintained. 

For  warming  large  buildings,  low  pressure  steam  may  be 
a  more  suitable  heating  medium,  and  in  the  case  of  factories 
and  workshops  where  steam  is  often  available  it  becomes 
unnecessary  to  provide  a  different  heating  medium.  Either 
live  or  exhaust  steam  is  suitable  for  warming  purposes. 

In  large  rooms,  where  a  big  number  of  people  congregate, 
a  heating  system  should  be  installed  which  can  be  readily 
cooled  down  should  the  place  get  overheated. 

When  the  amount  of  heat  that  is  stored  in  a  volume  of 
hot  water  is  compared  with  the  amount  of  heat  contained  in 
an  equal  volume  of  steam,  it  will  be  found  that  the  latter 
contains  less  than  one-hundredth  the  amount  of  the  former, 
when  the  temperatures  of  the  water  and  steam  are  180°  and 
228°  F.  respectively.  Thus  it  is  evident  that  water  is  com- 
paratively slow  in  giving  up  its  heat,  and  therefore  not  so  suited 
as  steam  where  quick  fluctuations  of  temperature  are  desired. 

Systems  of  Piping. — There  are  three  general  ways  for 
arranging  the  piping  in  connection  with  low  pressure  hot- 
water  apparatus — 

(a)  One  pipe  system. 
(&)  Two  pipe  system, 
(c)  Overhead,  or  drop  system. 


427 


428      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 


In  the  one  pipe  system  the  main  circuit  is  everywhere  of 
the  same  diameter,  whilst  in  a  two  pipe  system  the  mains  are 
sized  according  to  the  amount  of  heating  surface  to  be  served. 
The  overhead  or  drop  system  consists  mainly  of  vertical 
returns,  and  represents  a  modification  and  combination  of  the 
one  and  two  pipe  sytems. 

Fig.  262  shows  a  one  pipe  system  when  arranged  for  a 
single  storey  building,  and  it  will  be  observed  that  the  flow 
and  return  connections  to  and  from  each  radiator  join  the  same 


FIG.  262. — One  pipe  system. 

main.  In  this  system  the  cooled  water  from  the  heating 
surfaces  mixes  to  a  certain  extent  with  the  heated  water  from 
the  boiler,  and  where  a  circuit  is  very  long  the  water  near  the 
end  may  have  a  very  low  temperature.  Where,  however,  the 
pipes  are  of  a  suitable  size,  the  connections  properly  arranged, 
and  the  circuits  not  unduly  long,  the  drawback  mentioned  is  not 
so  apparent,  as  the  hottest  water  accommodates  itself  in  the 
upper  parts  of  the  horizontal  pipes,  whilst  the  colder  water 
occupies  the  lower  parts. 

To  obviate  any  unnecessary  cooling  of  the  water  in  a  one 


LOW    PRESSURE    HOT-WATER    HEATING    APPARATUS      429 

pipe  system,  the  returns  from  the  heating  surfaces  should  be 
joined  at  the  side  of  the  horizontal  mains,  in  order  that  the 
colder  water  may  be  delivered  directly  to  the  lower  parts. 

It  is  important,  when  arranging  mains,  that  no  air  locking 
shall  take  place,  and  to  avoid  this  air-relief  pipes  require  to  be 
fixed  at  the  highest  points.  Kadiators  when  connected  to 
horizontal  pipes  also  require  to  be  provided  with  some  form 
of  air  relief. 

In  Fig.  262  the  main  from  the  boiler  to  point  A  constitutes 
the  flow,  whilst  that  part  of  the  circuit  from  A  to  the  boiler 
forms  the  return.  B  may  also  be  made  the  highest  part  of  the 
circuit,  the  return  starting  from  that  point. 

The  feed  cistern  of  an  apparatus  is  usually  fixed  in  any 
convenient  place  above  the  highest  heating  surface,  and  the 
supply  pipe  may  either  join  the  boiler  or  the  return  pipe,  as 
found  most  convenient.  It  is  not  necessary  to  fix  a  feed 
cistern  more  than  2  or  3  feet  above  the  top  of  the  highest 
radiator,  and  to  exceed  this  serves  no  useful  purpose,  but  it 
subjects  an  apparatus  to  unnecessary  strain. 

With  regard  to  the  point  where  a  flow-pipe  should  join  a 
radiator,  it  matters  little  in  many  cases  whether  it  be  at  the 
top  or  at  the  bottom  of  the  radiator.  Generally  speaking,  the 
best  results  are  obtained  by  joining  the  flow-pipe  to  the  top, 
although  the  bottom  connection  is  the  neater  of  the  two, 
especially  when  the  branch  is  rather  large.  The  inlet  of  each 
radiator  should  be  controlled  by  a  stop  valve,  in  order  that  the 
temperature  of  the  water  can  be  modulated  as  required. 

When  a  building  is  two  or  more  storeys  high,  a  good 
method  of  piping  for  a  one  pipe  system  is  that  shown  in  Fig. 
263.  Where  possible  the  heating  surfaces  on  the  upper  and 
on  the  lower  floors  should  be  over  one  another,  so  as  to  reduce 
the  number  of  risers  which  serve  them.  The  return  risers 
should  join  at  the  side  of  a  main,  whilst  the  flow  riser  in  the 
majority  of  cases  should  be  taken  from  the  top.  Each  pair  of 
risers  forms  a  secondary  circuit  from  the  main  circuit,  and 
under  ordinary  conditions  a  good  circulation  through  the  risers 
is  assured. 

In  Fig.  263  the  boiler  is  assumed  to  be  centrally  placed, 
and  to  the  left  and  right  main  circuits  are  provided.  When  a 


430      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


building  is  large,  the  number  of  principal  circuits  can  be 
increased,  and  this  practice  is  commendable,  as  the  lengths  of 
the  circuits  may  be  diminished,  and  better  results  obtained. 
One  section  can  also  be  put  out  of  use  without  interfering 
with  the  working  of  the  remainder  of  the  installation. 

The  cold  water  supply  in  Fig.  263  is  shown  joined  at  the 
end  of  one  of  the  circuits,  where  an  air-pipe  is  also  pro- 
vided. 

A  one  pipe  system  has   the   special  advantage  of   being 


FIG.  263. — One  pipe  system  with  flow  and  return  risers. 

immune   from  short  circuiting,  and   in   consequence  can  be 
adopted  where  a  two  pipe  system  would  result  in  failure. 

A  two  pipe  system  is  shown  in  Fig.  264,  and  the  manner 
in  which  it  differs  from  a  one  pipe  system  is  in  its  circuit  being 
graded  and  in  the  riser  returns  joining  the  main  return.  The 
maximum  size  of  the  flow-pipe  starts  at  the  boiler,  and  its 
size  is  decreased  as  the  heating  surface  is  supplied,  until  the 
head  of  the  circuit  is  reached.  From  the  latter  point  the 
circuit  forms  a  return,  and  it  is  increased  in  size  as  the  branch 
returns  are  joined  with  it.  The  chief  drawback  of  a  two  pipe 
system  is  its  liability  to  short  circuit,  and  for  a  portion  of  a 
system  to  be  either  rendered  useless  or  be  very  much  impaired. 
Short  circuiting  takes  place  when  too  much  resistance  is 
encountered  by  the  circulating  water,  but  this  may  be  due  to 


LOW   PRESSURE   HOT-WATER   HEATING    APPARATUS      431 


the  improper  grading  of  the  pipes,  to  the  latter  having 
insufficient  pitch,  or  to  pipes  being  dipped  or  trapped. 

The  chief  merit  of  a  two  pipe  system,  when  well  designed 
and  properly  installed,  is  that  the  cooled  water  from  the  heat- 
ing surfaces  is  delivered  directly  to  the  return,  instead  of 
mixing  with,  and  cooling,  the  heated  water  in  the  flow-pipe. 
This  point  is  very  important  in  large  buildings  where  long 
circuits  are  imperative. 

For  a  two  pipe  system  to  be  a  success,  the  pipes  require  to 
be  properly  sized,  and  be  given  a  moderate  pitch.  Dips  must 


FIG.  264. — Two  pipe  system  with  flow  and  return  risers. 

be  avoided,  and  suitable  fittings  used,  and  unless  these  pre- 
cautions are  observed  short  circuiting  will  take  place  to  a 
more  or  less  extent. 

Pitch  of  Pipes. — Where  practicable,  heating  mains  should 
have  a  pitch  of  1  inch  in  10  feet,  and  for  small  sized  branches 
the  pitch  should  not  be  less  than  1  inch  per  foot.  When  a 
main  is  of  a  comparatively  small  bore,  and  fixed  quite  level, 
the  movement  of  the  water  through  it  is  considerably  retarded. 

Overhead  or  Drop  System. — A  very  suitable  method  of 
piping  for  high  buildings,  and  where  the  heating  surfaces  can 
be  arranged  to  come  above  one  another,  is  the  overhead  or 
drop  system,  Fig.  265.  In  this  system  the  flow -pipe  passes 
directly  from  the  boiler  to  a  high  elevation,  where  an  air-pipe 
is  provided.  From  the  highest  point  one  or  more  overhead 


432      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


horizontal  pipes  are  taken  (depending  upon  the  size  of  the 
building),  and  from  the  latter,  vertical  returns  are  dropped  to 
pass  close  by  the  heating  surfaces.  No  work,  as  a  rule,  is  put 
upon  the  flow-pipe,  and  no  other  air-escapes  in  the  form  of 
valves  or  pipes  may  be  necessary,  other  than  that  at  the  head 
of  the  flow-pipe.  Air  is  chiefly  given  out  from  water  when  the 


^§m»^^ 

FIG.  265. — Overhead  or  drop  system. 

latter  is  heated,  and  the  liberated  air  rises  and  escapes  at  the 
highest  point.  After  the  water  leaves  the  boiler  a  cooling 
action  sets  in,  with  the  result  that  little  air  is  given  out  from 
the  water  when  in  the  return  pipes.  To  the  vertical  return 
No.  1,  horizontal  connections  are  shown  between  it  and  the 
radiators,  but  these  should  only  be  short  when  this  form  of 
connection  is  adopted.  A  better  mode  of  arranging  the  con- 


LOW   PRESSURE   HOT-WATER    HEATING    APPARATUS      433 

nections  is  that  on  the  vertical  return  No.  2,  where  tees  are 
used  which  aid  the  circulation  through  the  surfaces. 

Owing  to  the  large  amount  of  vertical  piping  in  an  overhead 
system,  a  quick  circulation  is  ensured,  and  in  consequence  the 
pipes  can  be  smaller  than  in  other  systems,  where  a  greater 
proportion  of  horizontal  pipes  are  used  and  where  the  circula- 
tion is  slower.  The  horizontal  overhead  and  low  level  returns 
require  to  be  graded  as  regards  their  size,  according  to  the 
amount  of  work  put  upon  them.  The  vertical  returns 
which  serve  the  radiators  are  of  uniform  bore  from  end 
to  end. 

It  frequently  occurs  when  arranging   the   piping  for  an 


FIG.  266. — One  pipe  system  where  circuit  dips  beneath  doorways. 

installation  that  obstructions  require  to  be  passed.  To  attain 
this  end  the  formation  of  one  or  more  dips  may  be  unavoidable, 
but  as  they  impede  circulation  they  should  be  avoided  as  far 
as  possible.  The  best  system  of  piping  where  dips  are  im- 
perative is  the  one  pipe  system,  but  as  regards  the  general 
arrangement  of  pipes  for  all  cases  no  hard-and-fast  rules  can 
be  laid  down. 

In  Fig.  266  a  case  is  shown  where  a  couple  of  doorways 
come  in  the  line  of  piping,  and  in  order  to  pass  them  the  flow- 
pipe  is  carried  up  and  over  them.  The  remaining  part  of  the 
circuit  from  the  air-pipe  forms  a  return,  and  instead  of  taking 
the  latter  back  and  over  the  doorways  it  is  dipped  beneath  them 
as  shown.  By  rising  the  flow-pipe  and  keeping  the  return-pipe 
low  the  circulating  head  is  increased,  and  this  overcomes  to  a 
28 


434     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

great  extent  the  retardation  introduced  by  the  trapped  return. 
At  A,  Fig.  266,  an  air-pipe  is  shown  in  order  to  liberate  air, 
which  tends  to  gather  at  that  point  either  when  charging  the 
apparatus  or  when  the  latter  is  in  use. 

The  Circulating  Head  is  the  vertical  distance  between  the 
highest  part  of  a  flow-pipe  and  the  fire-bars  of  a  boiler,  and 
the  power  to  produce  circulation  is  the  difference  in  density 
between  the  ascending  and  descending  columns  which  consti- 
tute the  flow  and  the  returns. 

Another  one  pipe  system  is  shown  in  Fig.  267,  where  the 


FIG. '267. — One  pipe  system  where  circuit  dips  beneath  doors. 

pipe  requires  to  be  dipped  beneath  a  number  of  doorways. 
In  this  case  radiators  are  fixed  on  each  of  two  floors.  The  flow- 
pipe  passes  directly  from  the  top  of  the  boiler  to  the  upper 
floor,  and  it  is  supposed  to  be  carried  up  to  near  the  ceiling  in 
order  to  give  extra  power  for  circulating  the  water  through 
the  dipped  return.  Only  two  air-pipes  are  necessary,  as  at  x 
and  y,  for  any  air  which  finds  its  way  into  any  other  part  of 
the  circuit  will  rise  and  accumulate  in  the  radiators.  From 
the  latter  air  can  be  periodically  released  by  opening  the 
air-cocks. 

Sizes  of  Pipes. — The  following  table  gives  the  aproximate 


LOW   PRESSURE   HOT-WATER   HEATING   APPARATUS      435 


amount   of   heating  surface    supplied    by    different  sizes   of 
pipes : — 

TABLE  XVI. 


Internal  diameter 
of  pipe. 

Square  feet  of 
surface,  chiefly 
horizontal  pipes. 

Square  feet  of 
surface,  horizontal 
and  vertical  pipes. 

Square  feet  of 
surface,  vertical 
pipes. 

1    in. 

40 

50 

75 

u 

75 

90 

130 

H 

130 

150 

250 

2 

230 

360 

600 

24 

360 

500 

800 

3 

520 

650 

1100 

4 

900 

1280 

2500 

5 

1600 

2000 

6 

2300 

3460 

8 

4600 

6150 

10 

8000 

10,400 

12 

11,520 

14,000 

With  regard  to  the  size  of  branches  and  radiator  con- 
nections, these  are  given  below. 

Less  than  50  sq.  feet  heating  surface  1    in.  diameter. 

More  than  50        „          „    and  less  than  80,  1£    „         „ 

Over          80       „          „  1J    „ 

The  sizes  of  branches  should  also  be  regulated  by  their 
general  arrangement,  for  where  they  are  rather  long,  and 
portions  lie  flat,  they  may  advantageously  be  increased  in  size. 

Heating  Surfaces  take  the  form  of  pipes,  coils,  and 
radiators.  Either  of  the  two  latter  is  used  when  a  large  area 
of  heating  surface  requires  to  be  concentrated  in  a  com- 
paratively small  space.  Pipes  are  well  suited  for  warming 
works  and  horticultural  buildings,  but  for  residences,  offices, 
and  similar  buildings,  radiators  are  preferable. 

Eadiators  usually  have  their  surfaces  vertically  arranged, 
and  they  possess  advantages  over  other  forms  of  heating 
surfaces  in  that  they  are  neater  in  appearance  and  collect  less 
dust. 

Kadiators  are  made  in  many  plain  and  ornamental  forms, 
so  as  to  suit  any  particular  position  in  a  building.  The  best 
type  of  radiator,  when  the  heating  surfaces  are  exposed,  is  the 


436     DOMESTIC   SANITARY   ENGINEERING   AND   PLUMBING 

column  or  loop  class,  where  the  sections  are  spaced  to  enable 
the  whole  of  their  surfaces  to  be  readily  cleansed.  Fig.  268 
gives  a  single  column  radiator  by  the  Beeston  Foundry  Co., 
each  section  when  36  inches  high  contains  3J  square  feet  of 
surface.  Two  and  three  column  radiators  of  the  same  height 
contain  per  section  4  and  5f  square  feet  of  surface  respectively. 


FIG.  268. — Single  column  radiator  by  the  Beeston  Foundry  Co.  Ltd. 

There  are  two  methods  of  joining  the  sections  of  radiators. 
One  is  by  the  use  of  tapered  nipples,  which  are  inserted  in 
the  upper  and  lower  openings  of  the  sections,  and  where 
wrought-iron  tie  rods  are  used  to  bind  the  sections  together. 
The  other,  and  better  method,  is  by  left  and  right-hand 
screwed  nipples,  the  sections  being  tapped  to  suit. 

For  simple  systems  of  ventilation,  the  cold  inflowing  air 
is  often  warmed  by  means  of  ventilating  radiators.  When  a 


LOW    PRESSURE    HOT-WATER   HEATING    APPARATUS      437 

good  type  of  radiator  is  selected,  this  method  of  inlet  ventila- 
tion has  much  in  its  favour,  as  the  air  supply  can  be  readily 
controlled  and  all  parts  may  be  arranged  so  as  to  admit  of 
their  being  readily  cleansed. 

Fig.  269  shows  a  simple  form  of  ventilating  radiator.     In 


FIG.  269.— Ventilating  radiator  by  the  Beeston  Foundry  Co.  Ltd. 

this  case  baffle  plates  are  fitted  on  both  sides  of  an  ordinary 
single  column  radiator,  and  a  base  is  provided  to  admit  fresh 
air  at  the  back.  The  baffle  plates  are  held  in  position  by  lugs 
which  are  cast  on  them,  and  they  can  be  readily  removed  for 
cleansing  purposes. 

A  ventilating  radiator  of  the  flue  type  is  illustrated  in 
Fig.  270,  and  the  fresh  air  may  be  arranged  to  enter  at  the 
back  as  shown,  or  through  the  floor  beneath.  This  radiator 


438      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

is  also  designed  that   every  part   may  be   seen   and   readily 
cleansed. 

A  drawback  of  many  ventilating  radiators,  however,  is  their 
hidden  parts,  where  dust  and  other  matter  can  accumulate. 


FIG.  270.— The  "  Marshall"  ventilating  radiator  by  the 
Beestou  Foundry  Co.  Ltd. 


For  this  reason  ordinary  loop  radiators  are  often  used,  either 
with  air  grates  immediately  beneath  them  or  in  a  wall  behind. 
Of  course  when  the  ordinary  type  of  radiator  is  adopted  and 
where  baffle  plates  are  not  used,  the  air  is  not  warmed  so  well, 
and  there  is  greater  likelihood  of  draughts  being  felt.  Fig. 
271  gives  a  hinged  radiator.  This  is  a  very  useful  form  for 


LOW   PRESSURE   HOT-NVATER   HEATING    APPARATUS      439 

many  situations,  as  it  can  be  swung  from  the  wall  and  so 
enable  the  space  behind  to  be  readily  accessible. 

Comparative  Value  of  Heating  Surfaces. — The  relative 
amount  of  heat  emitted  by  a  surface  largely  depends  upon  the 
form  it  takes,  upon  its  roughness  or  smoothness,  and  to  some 
extent  upon  the  kind  of  metal  which  forms  the  surface. 


FNJ.  271. — The  "  Hospital  Hinged"  radiator  by  the  Beeston  Foundry  Co.  Ltd. 

When  heating  surfaces  are  exposed  to  view,  the  air  of  an 
apartment  is  warmed  in  two  ways,  viz.  by  radiant  and  by 
convected  heat. 

Radiant  heat  passes  from  its  source  in  straight  lines,  and 
is  absorbed  by  the  cooler  surfaces  of  walls,  furniture,  and  other 
objects.  The  intervening  air  space  is  not  very  appreciably 
warmed  by  radiant  heat,  as  air  alone  is  not  warmed  by  direct 


440      DOMESTIC   SANITARY    ENGINEERING    AND   PLUMBING 

rays  of  heat.  Air,  however,  in  buildings  always  contains 
floating  particles  of  matter  which  absorb  a  certain  amount  of 
heat,  and  these  in  turn  give  up  some  of  the  heat  they  have 
received  to  the  air  which  envelopes  them. 

Converted  heat  is  that  which  is  absorbed  by  air  coming  in 
contact  with  heating  surfaces,  or  by  contact  with  objects 
which  have  been  warmed  by  radiant  heat. 

Eadiant  heat  can  be  intercepted  by  means  of  a  screen, 
whilst  convected  heat,  which  is  conveyed  by  the  circulating 
air,  cannot  be  cut  off  by  this  means. 

Small  pipes  emit  more  heat  per  unit  area  of  surface  than 
larger  ones,  when  the  difference  in  temperature  between  the 
pipes  and  the  air  surrounding  them  is  the  same,  and  when 
the  rate  of  circulation  is  also  equal. 

Heating  surfaces  when  grouped  close  together,  such  as  in 
coils  and  radiators,  emit  less  heat  than  where  they  are  farther 
apart ;  in  the  former  case  a  large  percentage  of  the  radiant  heat 
is  not  utilised  for  warming  purposes,  as  it  cannot  get  away, 
but  is  simply  radiated  and  re-radiated  from  surface  to  surface. 
The  efficiency  of  heating  surfaces  is  also  affected  by  their 
height,  for  air  currents,  upon  being  warmed  by  contact  at  a 
low  level,  absorb  less  heat  as  they  ascend.  From  the  above 
it  will  be  clear  that  the  most  efficient  radiator  is  the  single 
column  class,  when  the  sections  are  a  reasonable  distance 
apart. 

Polished  copper,  brass,  or  nickel  plated  pipes  emit  less 
heat  per  unit  area  than  other  surfaces. 

The  positions  in  which  the  greater  percentage  of  the 
heating  surfaces  should  be  placed  are  in  the  coldest  parts  of  a 
building.  These,  obviously,  are  the  windows,  external  walls, 
and  near  doorways.  In  buildings  of  considerable  width  it  is 
necessary  to  fix  heating  surfaces  in  other  positions  than  those 
stated,  in  order  that  warmth  can  be  evenly  distributed  through- 
out the  whole  space. 

Kadiators  should  be  fixed  about  6  inches  from  walls  where 
practicable,  otherwise  there  is  greater  likelihood  of  the  latter 
being  soiled.  Air,  upon  being  warmed,  leaves  the  heating 
surfaces  with  more  or  less  considerable  velocity,  with  the 
result  that  particles  of  dust  which  the  air  contains  stride 


LOW    PRESSURE   HOT-WATER    HEATING    APPARATUS      441 

against  any  adjoining  wall  and  discolour  it.  Discoloration  of 
walls  may  also  be  avoided  by  the  use  of  light  shields,  which 
are  occasionally  placed  on  the  tops  of  radiators  to  divert  the 
air  currents  towards  the  centre  of  the  apartments. 

Radiator  Valves.  —  A  suitable  pattern  of  valve  is  that 


FIG.  272. — Angle  valve  by  the  National  Radiator  Co.  Ltd. 

shown  in  Fig.  272,  and  it  allows  a  neat  and  simple  connection 
to  be  made.  Whatever  form  of  valve  is  used,  one  should  be 
selected  which  does  not  unduly  impede  the  movement  of  the 
water. 

Air-Valves. — To  admit  of  the  escape  of  air  from    pipes 
and  heating  surfaces,  air-valves  are   frequently  used,     These 


442      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 

may  be  divided  into  two  classes:  (a)  Those  which  are 
periodically  opened  by  hand;  (b)  those  which  are  automatic 
in  action. 

The  latter  are  suitable  for  a  circuit  where  an  air-pipe 
cannot  be  fixed.  A  simple  form  of  automatic  air- valve  is 
given  in  Fig.  273.  Its  action  is  as  follows :  If  we  assume  that 
the  valve  is  closed  by  the  ball  being  partially  submerged,  the 


FIG.  273. — The  "Ideal"  automatic  air  valve  by  the 
National  Radiator  Co.  Ltd. 

air  passes  through  the  water  to  the  upper  part  of  the  valve. 
Should  the  accumulation  of  air  be  continuous,  the  water  is 
displaced  from  the  small  pocket,  when  the  ball  falls  by  its 
own  weight,  opens  the  valve,  and  permits  the  air  to  escape. 
The  discharge  of  air  is  followed  by  water  and  the  ball  is 
again  buoyed  up  and  the  orifice  closed. 

Feed  Cisterns. — The  size  of  feed  cisterns  should  be 
sufficient  to  accommodate  the  increased  volume  of  water, 
when  the  latter  is  raised  in  the  apparatus  to  its  maximum 


LOW    PRESSURE   HOT-WATER   HEATING    APPARATUS      443 

temperature.  Approximately,  water  expands  YV  °f  its  bulk 
when  raised  from  40°  to  212°  F.  The  highest  water-line 
of  a  cistern  should  be  a  few  inches  beneath  the  overflow,  and 
the  ball-cock  should  be  arranged  to  close  when  a  cistern 
contains  only  a  few  inches  of  water. 

As  regards  the  size  of  a  supply  pipe  which  communicates 
between  the  feed  cistern  and  the  apparatus,  this  should  not,  as  a 
rule,  be  less  than  1  inch  diameter.  A  dip  or  trap  is  necessary 
in  a  feed-pipe  to  prevent  hot  water  circulating  back  to  the 
supply  cistern,  and  when  the  circulation  in  a  system  is  liable 
to  be  sluggish  a  deeper  trap  than  usual  should  be  formed. 

Calculation  of  Heating  Surface. — Windows,  roof  lights, 
and  external  walls  are  the  principal  cooling  surfaces  in  build- 
ings, and  the  renewal  of  air  for  ventilation  is  also  responsible 
for  more  or  less  considerable  absorption  of  heat.  Doorways, 
floors,  internal  walls  and  crevices,  also  account  for  loss  of  heat, 
and  in  countries  where  the  cold  is  very  intense  these  are  also 
taken  into  account.  In  the  British  Isles,  however,  it  is  usually 
sufficient  to  consider  the  principal  heat  losses,  such  as  those 
due  to  glass  surface,  external  walls,  ventilation,  and  the  ex- 
posure of  buildings.  To  cover  minor  heat  losses  an  allowance 
of  10  per  cent,  of  the  above  is  usually  ample. 

Discharge  of  Air  through  Flues. — To  calculate  the  actual 
volume  of  air  which  will  constantly  pass  through  a  flue  or 
opening  when  the  movement  of  air  is  dependent  upon 
natural  agencies  is  impossible. 

The  volume  of  air  which  will  flow  through  an  ordinary 
chimney  varies  considerably,  the  actual  discharge  being  governed 
by  the  height,  size,  and  form  the  flue  takes,  by  the  difference 
between  internal  and  external  temperatures,  by  the  freedom 
with  which  air  can  enter  a  room,  and  by  the  kind  of  walls  in 
which  the  flues  are  formed.  It  is  thus  clear  that  discretion 
requires  to  be  exercised  when  ascertaining  the  probable  average 
discharge  of  air  through  any  opening  or  extract  shaft.  On  an 
average,  when  a  fire  is  burning  the  discharge  of  air  per  sq.  foot 
of  flue  area  is  about  11,000  cubic  feet  per  hour. 

If  a  building  is  already  erected,  the  velocity  of  air  through 
an  opening  can  be  determined  by  an  air-meter,  but  the  records 
will  vary  considerably.  It  is  usual,  however,  to  take  a  number 


444     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

of  readings,  the  mean  velocity  being  used  for  the  basis  of 
calculation.  In  this  case  the  volume  of  air  discharged  by  a 
flue  will  equal  the  area  of  its  cross  section,  multiplied  by  the 
mean  velocity  in  feet. 

When  an  air-meter  cannot  be  used  the  following  formula 
will  aid  in  ascertaining  the  discharge  of  air  through  an 
upcast  shaft  :  — 

.  (88) 


Where  Q  =  discharge  in  cubic  feet  per  hour. 
„       a  =  area  of  cross  section  of  flue  in  inches. 
„       li  =  height  of  flue  in  feet. 
„       T  =  temperature  of  air  in  flue. 
„        t  —  external  temperature  of  air. 

Example,  53.  —  If  a  15  in.  by  9  in.  duct  is  24  feet  high,  and 
the  external  and  internal  air  temperatures  are  45°  and  60°  F. 
respectively,  determine  the  approximate  volume  of  air  this 
duct  should  discharge  per  hour. 

By  Formula  88,  Q  =  80  x  a  X 

Substituting  values  given, 

,  K     n        /24x  (60-45) 
V  J 


Q  =  80xl5x9x-844; 
/.  Q  =  9115  cubic  feet. 

Assuming  that  a  heating  coil  had  been  placed  at  the  base 
of  the  duct  in  order  to  raise  the  escaping  air  to  80°  F.,  the 
velocity  of  air  through  the  shaft  would  have  been  increased. 
Under  these  conditions  the  discharge  should  be 


460  +  45     ' 
Q  =  80x  15x9x1-289; 
.-.  Q  =  139,21  cubic  feet. 

Heat  to  Warm  Air.  —  To  raise   1   cubic  foot  of  air  from 
30°  to  31°  F.  requires  '01928  B.T.U.,  so  that  the  volume  of 


LOW  PRESSURE  HOT-WATER  HEATING  APPARATUS  445 
air  which  can  be  raised  through  1  degree  by  one  heat  unit 
will  be  ,niQOQ  =  51'86  cubic  feet.  In  order  to  simplify  matters 

'OLuZo 

we  will  take  the  latter  value  at  50  cubic  feet,  and  this  will  be 
sufficiently  accurate  for  practical  work. 

Thus  the  number  of  heat  units  necessary  to  make  good  the 
loss  of  heat  due  to  ventilation  can  be  obtained  by  multiplying 
the  total  volume  of  air  in  feet  by  the  temperature  through 
which  the  air  is  raised  and  by  afterwards  dividing  by  50. 

Heat  absorbed  by  Walls. — The  heat  lost  by  walls  varies 
according  to  their  thickness,  to  the  class  of  material  used, 
to  the  treatment  of  their  surfaces,  whether  cavities  are  formed 
in  them  or  not,  and  according  to  their  relative  exposure.  The 
values  given  by  different  authorities  vary,  but  the  most  reliable 
information  on  this  matter  known  to  the  writer  is  that  given 
in  the  German  work  by  Recknagel  and  Eietschel.  Tables 
XVII.  and  XVIII.  are  from  that  work,  but  the  values  are 
converted  into  English  Units  by  Professor  Kinealy  and  given 
in  book  Formulas  and  Tables  for  Heating. 


TABLE  XVII. 
Loss  OF  HEAT  THROUGH  BRICK  WALLS  IN  BRITISH  THERMAL 

UNITS  PER  SQUARE  FOOT  OF  SURFACE  PER  HOUR,  PER 
DEGREE  DIFFERENCE  OF  TEMPERATURE,  THE  BRICKS  BEING 
8J  X  4  X  2  IN.,  WITH  f  IN.  MORTAR  JOINTS 


Outside  walls. 

Inside 

With  additional  stone  face. 

With  air 

wall, 

space 

Thickness 

both 

of  2-4 

of  wall. 

No 
plaster. 

One  side 
plas- 
tered. 

sides 
plas- 
tered. 

4  in. 

thick. 

Sin. 
thick. 

12  in. 
thick. 

inches 
plas- 
tered. 

£  brick 

•52 

•49 

•43 

1        , 

•37 

•36 

•33 

•31 

•29 

•26 

•25 

H      , 

•29            '28 

•26 

•25 

•23 

•21 

•21 

2    bricks 

•25            '24 

•22 

•20 

•19 

•19 

21 

•22 

•21 

•19 

•18 

•17 

•16 

32 

•19 

•18 

•17 

•16 

•15 

•14 

31 

•16 

•16 

•15 

•14 

•13 

•13 

4 

•14 

•14 

... 

... 

... 

•12 

4£       , 

•12 

•12 

... 

... 

i 

446      DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 


TABLE  XVIII. 

Loss  OF  HEAT  THROUGH  STONE  WALLS  IN  BRITISH  THERMAL 

UNITS     PER    SQUARE    FOOT     OF     SURFACE    PER    HOUR,    PER 
DEGREE  DIFFERENCE   OF  TEMPERATURE 


Total  thick- 
ness of  wall. 

Sandstone. 

Limestone. 

Total  thick- 
ness of  wall. 

Sandstone. 

Limestone. 

12  inch 

•45 

•49 

32  inch 

•26 

•28 

16    „ 

•39 

•43 

36    „ 

•24 

•26 

20    „ 

•35 

•38 

40    ,, 

•22 

•24 

24    ,, 

•31 

•35 

44    „ 

•21 

•23 

28    „ 

•28 

•31 

48    „ 

•19 

•21 

HEAT  LOST  BY  GLASS  SURFACE 

This  is  given  in  the  following  table  along  with  other  partic- 
ulars. The  values  given  by  the  two  authorities  differ  a  little, 
but  not  to  any  considerable  extent : — 

TABLE  XIX. 


Authorities. 

Kind  of  surface. 

Recknagel  and 
Rietschel. 

German  Government 
standard. 

Single  windows 

1-03 

T09 

Double      ,,                        :          . 

•472 

•518 

Single  skylight 

1-092 

1-118 

Double      „ 

•492 

•621 

Doors    . 

•410 

•414 

Fireproof  floor 

•124 

,,          ceiling 

... 

•145 

Plaster  1'6  to  2  '6  in.  thick 

•615 

,,       2-6  to  3'2  in.      ,, 

•492 

... 

(1) 

(2) 

(3) 

The  total  heat  lost  in  B.T.U.  by  walls  and  glass  can  be 
obtained  by  multiplying  the  exposed  area,  by  the  difference 
of  the  air  temperature  on  the  two  sides,  and  afterwards  by  a 
suitable  value  from  Tables  XVII.  to  XIX. 

According  to  Professor  Kietschel  the  values  in  Tables  XVII. 
and  XVIII.,  and  also  those  in  column  2  of  Table  XIX.,  should 
be  increased  as  stated  below. 

When  the  exposure  is  a  northerly  one,  and  the  winds  are 
important  factors,  increase  by  10  per  cent. 


LOW   PRESSURE   HOT- WATER   HEATING    APPARATUS      447 


Where  a  building  is  heated  during  the  daytime  only,  and 
is  not  an  exposed  one,  increase  by  10  per  cent. 

Where  a  building  is  exposed,  and  only  heated  during  the 
daytime,  increase  by  30  per  cent. 

Where  a  building  is  heated  intermittently  during  the  winter 
months,  and  with  long  intervals  of  non-heating,  increase  by 
50  per  cent. 

In  order  to  arrive  at  the  amount  of  heating  surface  to 
warm  a  building,  we  must  next  know  how  many  heat  units 
are  emitted  by  such  surface.  The  precise  amount  of  heat 
emitted  chiefly  depends  upon  the  form  the  surfaces  take,  and 
upon  the  difference  in  temperature  between  the  surfaces  and 
the  atmosphere  which  envelopes  them.  Professor  Carpenter  of 
Cornell  University,  in  his  work  Heating  and  Ventilating  Build- 
ings, gives  the  following  values,  which  are  reproduced  in  the 
table  below : — 

TABLE  XX. 

HEAT  UNITS  EMITTED  PER  SQUARE  FOOT  OF  HORIZONTAL  PIPE 
SURFACE  PER  HOUR,  FOR  DIFFERENT  RANGES  OF  TEMPERA- 


TURE    BETWEEN     THE 
SURROUNDING  THEM 


HEATING     SURFACE     AND     THE     AIR 


Total  B.T.U.  per  square  foot  per  hour. 

Ti^flfV^-^.  _-  ,,£ 

Jjinerence  01 
temperature 

Diameter  of  pipe. 

degrees  F. 

6  in. 

4  in. 

2  in. 

lin. 

40 

49-6       56-2 

59 

77 

50 

64-5 

73 

77 

100 

60 

79-8 

90 

95 

124 

70 

95-2 

108 

113 

148 

80 

112-0 

127 

133 

173 

90 

128 

147 

153 

199 

100 

147 

167 

175 

228 

110 

166 

188 

198 

257 

120 

184 

208 

219 

287 

130 

203 

230 

242 

318 

140 

223 

252 

266 

346 

150 

244 

276 

291 

378 

160 

265 

300 

316 

410 

170 

286 

324 

341 

443 

180 

307 

348 

367 

475 

190 

330 

375 

393 

512 

200 

356 

403 

415 

552 

448     DOMESTIC   SANITARY   ENGINEERING   AND   PLUMBING 

The  amount  of  pipe  heating  surface  can  now  be  obtained 
by  first  ascertaining  the  total  heat  losses  per  hour,  and  after- 
wards dividing  by  a  value  from  Table  XX.  which  agrees  with 
the  conditions  given. 

Example  54.  —  If  a  room  contains  200  sq.  feet  of  external 
sandstone  wall  which  is  20  inches  thick,  60  sq.  feet  of 
glass,  and  10,000  cubic  feet  of  air  at  a  temperature  of  30°  F. 
are  passed  into  it  per  hour,  determine  the  area  of  4-inch 
pipe  surface  which  will  maintain  an  internal  temperature  of 
60°  F.  when  the  average  temperature  of  the  water  in  the 
pipes  is  160°  F. 

Heat  absorbed  by  Air.  —  The  air  required  for  ventilation  is 
10,000  cubic  feet  per  hour,  and  to  raise  this  from  30°  to  60° 
requires 


oU 


Loss  by  Wall  Surface.  —  In  Table  XVIII.  the  loss  through 
a  sandstone  wall  when  twenty  inches  thick  is  '35  B.T.U.  per  sq. 
foot  per  hour  per  degree  difference  of  temperature.  The  loss 
therefore  by  200  square  feet,  when  the  difference  in  tempera- 
ture between  the  internal  and  external  surfaces  is  (60  —  30)  = 
30°,  will  be 

200  x  30  x  -35  =  2100  B.T.U. 

Loss  of  Heat  by  Glass.  —  The  heat  lost  by  glass  for  an 
ordinary  window  according  to  column  2,  Table  XIX.,  is  1*03 
B.T.U.  per  sq.  foot  per  degree  difference  of  temperature  per 
hour.  Therefore  the  loss  due  to  60  feet,  when  the  difference 
in  temperature  between  the  two  sides  is  (60  —  30)  =  30°,  will  be 

60x30x1-03  =  1854  B.T.U. 

The  heat  absorbed  by  air,  exposed  wall,  and  glass  equals 
6000  +  2100  +  1854=    9954  B.T.U. 
Adding,  for  minor  losses  due 
to  doorways,  ceilings,floors, 
etc.,  10   per   cent,  of  the 
above  =      995  B.T.U. 


The  total  heat  losses  will  equal  =  10,949  B.T.U. 


LOW   PRESSURE   HOT-WATER   HEATING    APPARATUS      449 

Heat  emitted  by  Pipe  Surface.  —  In  Table  XX.  the  heat 
emitted  by  a  sq.  foot  of  4-inch  pipe  surface  per  hour,  when  the 
difference  between  the  pipe  and  air  of  apartment  is  (160  —  60) 
=  100°,  is  given  at  167  B.T.U  ; 

.   '  .     ,     10949     ,,   94 

/.  heating  surface  required  =        ^   =60  ™  sq.  feet. 

By  following  the  calculation  it  will  be  evident  that  the 
provision  for  ventilation  has  a  big  influence  on  the  amount  of 
heating  surface  required.  The  area  of  exposed  wall  and  the 
amount  of  glass  are  also  very  important  factors. 

In  the  British  Isles  a  heating  installation  should  be  capable 
of  maintaining  an  inside  temperature  of  60°  F.  when  the  out- 
side air  is  30°  F.  In  America  and  other  countries,  where  the 
cold  is  intense  in  winter,  an  inside  temperature  of  70*  is 
usually  required  when  the  outside  air  is  at  zero. 

To  calculate  the  heating  surface  required  for  an  internal 
temperature  of  60°,  and  an  external  temperature  of  30°,  when 
the  average  temperature  of  the  water  is  160°,  the  following 
simple  formula  may  be  used  :  — 


Where  K  =  total  pipe  surface  in  sq.  feet. 

„       Q  =  cubic  feet  of  air  passing  through  apartment  per 

hour. 

„     W  =  area  of  exposed  wall  surface  in  feet. 
„       G  =  area  of  glass  in  feet. 

Badiator  Surface.  —  Eadiators  emit  less  heat  per  unit  area 
than  horizontal  pipes,  and  when  the  former  are  used  their 
heating  surface  should  be  increased  over  that  of  pipes  as 
follows  :  — 

For  plain  1  column  radiators  add    5  per  cent. 

9  10 

•"  AV/ 


Example  55.  —  A  large  room  contains  10,500  cubic  feet  of 
space,  870  square  feet  of  exposed  wall  surface,  and  250  square 
feet  of  glass.    If  the  air  of  the  room  is  changed  3  times  per  hour, 
29 


450      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

determine  the  amount  of  heating  surface,  when  single  column 
radiators  are  used  to  maintain  an  inside  temperature  of  60° 
when  the  external  air  is  30°  F.  Average  temperature  of  water 
in  pipes  160°  F. 

By  Formula  89,  E  =        +      +  ' 


10500x3  ,  870  ,  250 
Substituting  values  given,  E  =  —  T  --  '"TT     IT' 


Total  pipe  surface  =2287  sq.  feet. 
For  single  column  radiators,  plus 

5  per  cent.       .        .        .         —   114  sq.  feet. 

/.  total  radiator  surface  =  2401  sq.  feet. 

Heating  Surface  for  Drying  Rooms. — When  low  pressure 
hot-water  apparatus  is  utilised  for  drying  rooms,  the  following 
formula  may  be  used  for  obtaining  the  heating  surface 
required,  to  maintain  an  internal  temperature  of  80°  when 
the  outside  air  is  30°  F.,  and  when  the  average  temperature  of 
the  water  in  the  pipes  is  170°  F. : — 

Ra3140  +  T  +  20  +  3~    '  '     (90) 

Where  E  =  total  area  of  pipe  surface  in  square  feet. 
„      Q  =  volume  of  air  passed  through  room  per  hour. 
„    W  =  area  in  feet  of  external  walls. 
„       I  =  area  in  feet  of  internal  walls. 
„     G  =  area  of  glass  in  feet. 

To  obtain  satisfactory  results  in  drying  rooms,  free  ventila- 
tion is  necessary,  and  the  entering  air  should  be  diffused  as 
evenly  as  possible  throughout  the  whole  of  the  space. 

Example  56. — A  drying  room  measures  20  feet  in  length, 
12  feet  wide  and  12  feet  high.  The  area  of  the  external  wall 
surface  is  144  sq.  feet,  and  that  of  the  internal  walls  624  sq.  feet. 
There  is  no  glass.  If  the  ventilating  arrangement  provides 
for  5  air  changes  per  hour,  find  the  heating  surface  required 
to  give  an  inside  temperature  of  80°  when  the  outside  air  is 
30°  F. 


LOW    PRESSURE   HOT-WATER   HEATING    APPARATUS      451 


Using  Formula  90,  B  =        +++ . 


„  ,,.,..          ,         .         -p     20x12x12x5,144,624 
Substituting  values  given,  K  =-        ..  JA —     —  +  -^-+- 


140 


20 


.-.  E  =  154-5,  say  155  sq.  feet. 


The  area  of  a  pipe  surface  may  be  found  by  multiplying 
its  circumference  by  its  length,  or  the  following  rule  may  be 
used  :  — 

rfxllx*  (    , 

42 


Where  A  ==  area  of  surface  in  feet. 

„        d  =  external  diameter  of  pipe  in  inches. 
„         1  =  length  of  pipe  in  feet. 

For  approximations,  it  may  occasionally  be  desirable  to 
calculate  the  heating  surface  for  warming  a  building  from  its 
cubic  capacity.  This  method  is  not  accurate  for  isolated 
apartments,  as  the  chief  factors,  such  as  exposed  walls,  glass 
surface,  and  ventilation,  differ  much  in  different  parts  of  a 
building. 

The  following  Table  gives  the  approximate  number  of  cubic 
feet  of  space  warmed  to  different  temperatures  by  one  square 
foot  of  pipe  surface,  when  the  outside  air  is  about  30°  F.,  and 
water  in  the  pipes  not  less  than  160°  F.  :  — 

TABLE  XXI. 


Kind  of  building  heated. 

Inside 
temperature 

Space  warmed  by 
1  square  foot  of 

Fahr. 

surface. 

Workshops  and  factories 

50° 

130  cubic  feet. 

Warehouses  . 

55° 

100 

Churches  and  large  rooms 

60° 

86 

Living  rooms 

60° 

58 

•        • 

65° 

50 

Entrance  halls 

70° 

42 

f 

75° 

34 

Drying  rooms      .         .         .        .« 

80° 
85° 

27 
22 

I 

90° 

18 

452      DOMESTIC    SANITARY    ENGINEERING   AND    PLUMBING 

Boilers  for  Low  Pressure  Heating  Apparatus. — For  medium 
and  large-sized  installations,  independent  cast-iron  sectional 
boilers  are  superseding  those  of  wrought  iron,  as  the  former 
are  more  durable,  and  their  heating  surfaces  can  be  more 
advantageously  shaped  and  arranged.  Brickwork  settings 
are  dispensed  with,  and  sectional  boilers  also  possess  the 
advantage  of  portability,  as  they  can  be  taken  through  narrow 
openings. 

Small  heating  systems  require  less  powerful  boilers  than 
the  cast-iron  sectional  type,  and  for  these  many  other  forms 
of  independent  boilers  can  be  readily  obtained. 

The  selection  of  a  boiler  should  be  governed  to  a  great 
extent  by  the  class  of  fuel  to  be  consumed.  Where  a  fuel 
such  as  anthracite  is  used,  smaller  and  more  tortuous  passages 
between  the  heating  surfaces  are  permissible,  in  order  to 
extract  as  much  heat  as  possible  from  the  fuel  consumed. 

Soft  bituminous  coals  require  a  simple  form  of  boiler, 
owing  to  the  amount  of  soot  deposited  in  the  flues.  All  boilers 
require  ample  provision  in  the  form  of  soot  doors,  to  enable 
the  heating  surfaces  to  be  periodically  freed  from  soot. 

Heating  surfaces  of  boilers  are  either  direct  or  indirect ; 
the  former  are  exposed  to  the  fire,  and  receive  the  flame 
impact,  the  radiant  heat  from  the  burning  fuel,  and  the 
heated  products  of  combustion.  Indirect  surfaces  are  those 
which  do  not  face  the  fire,  but  receive  their  heat  only  from 
more  or  less  flame  impact,  and  the  heated  products  of  com- 
bustion. Indirect  surfaces  absorb  considerably  less  heat  than 
direct  surfaces,  but  they  are  useful  as  they  deprive  the 
products  of  combustion  of  much  heat,  and  prevent  them 
escaping  from  the  boiler  at  an  unnecessarily  high  temperature. 

In  connection  with  indirect  boiler  surfaces  there  is  a 
tendency  to  overvalue  them.  It  is  often  stated  that  the  value 
of  indirect  surfaces  is  about  one-third  that  of  direct  surfaces,  but 
this  valuation  in  most  cases  is  considerably  overrating  them. 

A  general  comparison  of  the  value  of  direct  and  indirect 
boiler  surfaces  is  unsatisfactory,  for  very  much  depends  upon  the 
ratio  of  the  grate  area  to  the  heating  surface  and  the  design 
of  the  boiler.  From  a  test  made  with  a  boiler  which  had  a 
relatively  large  amount  of  indirect  heating  surface,  the  amount 


LOW  PRESSURE  HOT- WATER  HEATING  APPARATUS   453 

of  heat  transmitted  through  each  sq.  foot  of  surface  per 
hour  worked  out  at  2500  B.T.U.  The  difference  in  value  of 
the  heating  surface  in  contact  with  the  fire  and  that  most 
distant  was  considerable,  and  whilst  a  sq.  foot  of  surface 
most  favourably  located  would  transmit  10,000  B.T.U  and  over 
per  hour,  a  sq.  foot  farthest  removed  would  probably  not 
transmit  250  B.T.U  in  the  same  time.  Thus,  for  this  case, 
some  parts  of  the  indirect  surface  would  have  not  more  than 
one-fortieth  the  value  of  the  best  direct  surface,  area  for  area. 


FIG.  274.—"  White  Rose  "  boiler  by  Hartley  &  Sogden. 

Intermediate  parts  of  the  indirect  surface  would  have  a 
higher  value,  but  the  example  will  indicate  the  difficulty  of 
assigning  a  true  value  to  the  indirect  heating  surface  of  a 
boiler. 

Fig.  274  gives  one  of  Hartley  &  Sugden's  cast-iron 
sectional  boilers,  where  the  sections  are  vertically  arranged, 
and  joined  together  by  nipples  and  bolts.  The  upper  part  of 
each  section  is  constructed  to  form  a  centre  and  two  side  flues. 
At  the  fire-box  the  flames  and  heated  products  of  combustion 
envelope,  to  a  more  or  less  extent,  the  surfaces  immediately 


454     DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

overhead,  and  afterwards  they  pass  into  and  along  the  upper 
side  flues  towards  the  front  of  the  boiler,  and  thence  through 
the  centre  flue  back  to  the  chimney.  There  are  numerous 
waterways  which  increase  the  heating  surface,  and  the  grate 
area  is  proportional  to  the  number  of  sections  a  boiler  contains. 
This  type  of  boiler  is  made  in  different  sizes.  Their  lengths 
vary  from  3  ft.  4  in.  to  6  ft.  10  in.,  and  the  sections  have  a 
uniform  width  of  2  ft.  7  in.,  and  they  are  catalogued  to  heat 
from  575  to  2500  sq.  feet  of  radiator  surface. 

Another  type  of  cast-iron  sectional  boiler  by  Lumby  Sons, 
Wood  &  Co.  Ltd.,  is  given  in  Fig.  275.  This  is  a  larger  type 
than  that  given  in  Fig.  274,  and,  as  will  be  seen,  contains 
proportionally  more  horizontal  heating  surface.  The  course 
of  the  flames,  and  products  of  combustion,  after  passing 
between  the  surfaces  immediately  over  the  fire-box,  pass  along 
towards  the  front  of  boiler,  and  thence  to  the  chimney  through 
the  top  horizontal  flues.  This  pattern  of  boiler  is  made  in 
various  sizes,  the  greatest  length  being  6  ft.  2  in.  and  the 
shortest  2  ft.  8  in.  The  catalogue  ratings  of  these  boilers 
vary  from  1600  to  4000  sq.  feet  of  radiator  surface.  There  are 
many  makers  of  cast-iron  sectional  boilers,  and  the  boilers 
illustrated  are  only  intended  to  show  the  general  form  they 
take,  not  to  infer  that  they  are  superior  to  those  produced  by 
other  firms. 

The  "Trentham"  Cornish  boiler,  Fig.  276,  is  suitable  for 
large  high  buildings.  It  is  circular  in  form,  being  made  of 
f -inch  wrought-iron  plates.  For  this  boiler,  brickwork  settings 
are  required,  the  flues  being  arranged  that  the  heated  products 
of  combustion,  after  leaving  the  combustion  chamber,  can  pass 
under  the  lower  portion  of  the  boiler  towards  the  front,  and 
afterwards  back  over  the  upper  part  to  the  chimney.  A  water- 
way bridge  is  formed,  and  the  heating  surface  can  be  further 
increased  by  providing  cross  tubes  in  the  combustion  chamber 
as  shown.  The  "  Trentham "  boiler,  owing  to  its  shape,  is 
suitable  for  withstanding  high  pressure,  and  it  is  made  in 
sizes  from  2  ft.  8  in.  to  5  ft.  diameter,  and  from  4  to  18  feet 
in  length.  These  are  catalogued  as  being  capable  of  heating 
from  900  to  10,500  feet  of  4-inch  pipe. 

A  good  draught  is   required   for   boilers  with   long   and 


LOW    PRESSURE   HOT- WATER   HEATING    APPARATUS      455 

tortuous  flues,  and  the  height  of  a  chimney  should  exceed  the 
length  of  the  horizontal  flues. 


\  i 


Fig.  277  gives  a  simple  and  effective  form  of  wrought-iron 
boiler  when  the  cross  tubes  are  arranged  in  the  manner  shown. 


456      DOMESTIC   SANITARY    ENGINEERING    AND   PLUMBING 

The  chief  objection  to. this  type  of  boiler  is  its  height,  and  this 
limits  its  use  on  that  account. 


Section. 


Elevation. 
Fro.  276.—  Trenthani  boiler  by  Lumby  Sons,  Wood  &  Co.  Ltd. 


LOW    PRESSURE   HOT-WATER    HEATING    APPARATUS      457 

For  a  small  heating  installation  the  dome-top  boiler, 
Fig.  246,  or  one  of  a  similar  grade,  may  be  adopted.  The 
drawback  of  this  type  is  its  low  efficiency  as  a  heater,  but  it 
has  the  advantage  of  a  low  initial  cost.  When  the  heating 


FIG.  277.— "  Goliath  "  boiler  by  Lumby  Sons,  Wood  &  Co.  Ltd. 

surfaces  of  a  boiler  are  mainly  of  a  vertical  nature,  and  where 
there  is  a  large  clear  passage  to  the  outlet  flue,  the  greater 
portion  of  the  heat  given  out  from  the  fuel  escapes  into  the 
chimney. 

Boiler  Draught  Regulator. — An  automatic  device,  which  is 


458      DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 

shown  in  Figs.  255  and  256,  is  very  useful  for  controlling  the 
draught  of  a  boiler,  and  for  economising  fuel. 

To  prevent  unnecessary  loss  of  heat  from  boilers  and  main 
pipes,  these  should  be  covered  with  a  good  form  of  insulating 
material.  Various  substances  are  used  for  this  purpose,  but 
all  allow  a  certain  amount  of  heat  to  pass  through  them. 

Sizes  of  Boilers. — A  common  method  of  estimating  the 
power  of  a  boiler  is  to  assume  that  each  sq.  foot  of  its 
surface  will  transmit  sufficient  heat  to  supply  about  35  sq. 
feet  of  radiator  surface.  Taking  the  average  amount  of  heat 
emitted  by  a  single  column  radiator  as  160  B.T.U.  per  sq. 
foot  per  hour,  then  each  sq.  foot  of  boiler  surface  should 
transmit  160x35  =  5600  B.T.U.  per  hour.  For  a  normal  rate 
of  firing,  the  latter  value  is  very  much  higher  than  can  be 
obtained  in  practice,  and  such  basis  for  rating  boilers  which 
differ  so  widely  in  construction  is  a  very  inaccurate  and 
misleading  one.  The  amount  of  heat  which  is  transmitted 
by  a  sq.  foot  of  boiler  surface  is  not  a  fixed  quantity,  but 
depends  upon — (a)  the  design  of  the  boiler  ;  (b)  the  ratio  of  the 
grate  area  to  the  heating  surface  ;  (c)  the  rate  of  firing ;  and 
(d)  the  class  of  fuel  used.  In  operation,  the  condition  of  a 
boiler  flue  is  also  an  important  factor. 

More  failures  have  resulted  in  connection  with  heating 
systems  by  installing  boilers  which  are  too  small  than  by  any 
other  means.  Most  boiler  catalogues  are  considerably  over- 
rated, but  many  makers  introduce  a  kind  of  saving  clause  in 
which  they  recommend  that  a  larger  size  be  selected  than  the 
one  listed  to  do  the  work  required. 

In  the  following  Table  is  given  the  heat  value  in  British 
thermal  units  per  pound  of  different  fuels  (Moles worth's) :  — 


TABLE   XXII. 


Coal  average 

14,000  B.T.U. 

Coal  Lancashire  (steam) 

13,900  B.T.U. 

„    Welsh  (steam)    . 

16,000       ,, 

„     Newcastle    . 

14,000       ,, 

,,    Welsh  (medium) 

13,900       ,, 

Coke    .... 

12,500       „ 

,,    Scotch 

13,500       „ 

Coke  (gas)    . 

10,000       „ 

LOW   PRESSURE    HOT-WATER   HEATING    APPARATUS      459 

It  is  not  often  that  50  per  cent,  and  over  of  the  heat  in  the 
fuel  is  transmitted  through  the  surfaces  of  a  low-pressure  boiler, 
owing  to  the  latter  not  being  fired  to  advantage.  The  fuel  is 
often  added  at  long  intervals,  the  fire-box  being  sufficiently 
commodious  to  hold  in  many  cases  from  5  to  10  hours'  supply. 
These  slow  rates  of  combustion  give  a  low  efficiency,  and  for 
best  results  a  moderately  high  rate  of  firing  is  imperative. 

For  obtaining  the  size  of  boilers  the  formulae  beneath  are 
given — 

a  =  ^^  (92) 

wxfxc 

R=axwxfxc 

u 

Where  a  =  area  of  boiler  grate  in  feet. 

„      R  =  total   heating  surface  of   radiators  in  sq.  feet. 
„      w  =  heat   units  emitted   per   hour   per   sq.  foot  of 

radiator  surface. 
„      w  =  weight  of  fuel  in  Ib.  consumed  per  sq.  foot  of 

grate. 

„  c  =  a  coefficient,  the  value  of  which  depends  upon 
the  type  of  boiler  and  the  rate  of  firing  (see 
Table  XXIIL). 

„      /=heat  value  of  fuel  (see  Table  XXIL). 
For  radiators,  the  average  value  of  u  may  be  taken  as  160, 
and  for  values  of  pipes  see  Table  XX. 

TABLE  XXIIL 

VALUES  OF  c  FOR  DIFFERENT  FORMS  OF  HEATERS  AND 
DIFFERENT  RATES  OF  FIRING 


For  good  sectional  self-contained  boilers  .... 
„  Cornish  "  Trentham  "  boilers     
,,  vertical  self-contained  boilers  with  cross  tubes    . 
,,  self-contained  dome-top  boileis  

c=  -5    to  -65 
c='4    to  -55 
c='5    to  -6 
c='35  to  -45 

The  fuel  consumption  w  to  agree  with  the  values  of  c  is 
also  given.     For  very  low  rates  of  firing  the  values  of  c  will 


460      DOMESTIC   SANITARY    ENGINEERING    AND    PLUMBING 

decrease,  the  rate  of   firing  for  working  conditions   varying 
from  3  to  12  Ib.  of  fuel  per  sq.  foot  of  grate  per  hour. 
Boilers  set  in  brickwork   w  =  Q  to  9  Ib. 

Sectional  boilers  with  winding  flues  w  =  *J  to  10  Ib. 
Self-contained  vertical  boilers  w  =  8  to  12  Ib. 

Example  57.  —  If  a  system  contains  say  1500  sq.  feet  of 
heating  surface,  and  a  sectional  cast-iron  boiler  is  adopted,  find 
size  of  boiler  required  to  satisfy  a  rate  of  firing  of  8  Ib.  of  fuel 
per  square  foot  of  grate  per  hour.  Assume  the  coal  will  yield 
14,000  B.T.U.  per  Ib. 

By  Formula  92,  a=    R*.^   . 
wxfxc 

For  the  rate  of  firing  given,  the  value  of  c  will  be  say  -5. 

1500x160 
Substituting  values,  a  = 


/.  q  =  4'29  sq.  feet  of  grate. 

Should  a  higher  rate  of  firing  be  adopted  a  smaller  size  of 
boiler  would  suffice,  but  the  stoking  would  require  to  be  done 
at  shorter  intervals. 

For  the  boiler  and  conditions  given  in  Example  57,  the  fuel 
consumed  would  amount  to  4'29  x  8  =  34'32,  say  34  Ib.  per 
hour. 

Example  58.—  The  fire-grate  of  a  boiler  like  Fig.  277  has 
an  area  of  1*8  sq.  feet.  Find  the  amount  of  heating  surface 
this  boiler  will  serve,  if  coke,  which  has  a  heat  value  of  12,500 
B.T.U.  per  Ib.,  is  the  fuel  burned,  and  when  the  rate  of  firing  is 
9  Ib.  per  sq.  foot  of  grate  per  hour. 

Using  Formula  93,   E  = 


The  value  of  c  for  this  boiler  from  Table  XXIII.  for  the 
rate  of  firing  given  will  be  about  *5, 

_     l-8x9x!2,500x-5 
and  substituting  values,  E=  -        ~TfiO  "  ' 

.%  E  =  632-8,  say  633  sq.  feet. 

Chimneys.  —  Failure    of    boilers    is    occasionally   due    to 
defective  draught  owing  to  the  chimneys  being  too  small  or 


LOW   PRESSURE   HOT- WATER   HEATING    APPARATUS      461 

too  short,  containing  too  many  bends  or  being  formed  of  long 
lengths  of  exposed  metal  pipes. 

Circular  chimneys  offer  the  least  resistance,  and  for  small 
boilers  where  a  flue  is  formed  of  metal  pipes,  the  minimum 
diameter  should  be  5  inches.  "Where  possible,  a  boiler  should 
be  joined  with  a  brick  chimney,  as  the  latter  is  less  influenced 
by  the  weather.  The  effective  area  of  a  chimney  is  less  than 
its  actual  area  owing  to  the  soot  which  accumulates  on  the 
surface. 

To  determine  the  size  of  a  chimney  for  a  heating  installa- 
tion, the  following  formulas  may  be  used : — 

For  installations  containing  less  than  700  sq.  feet  of 
heating  surface 


/ 


(94) 


When   an   installation   contains   700   sq.  feet  of  heating 
surface  and  over 

/.r»r>  .  .  i  > 

(95) 


Where  d  —  diameter  of  chimney  in  inches. 
„      h  =  height  of  chimney  in  feet. 
„     K  =  total  heating  surface  of  radiators  and  pipes  in 

•  feet. 

In  the  case  of  a  square  chimney,  the  length  of  one  side  may 
be  considered  equivalent  to  the  diameter  of  a  circular  one. 

Example  59.  —  Determine  the  size  of  a  chimney  when  its 
height  is  36  feet  for  a  system  containing  850  sq.  feet  of 
heating  surface. 


By  Formula  95,  ^=, 

JK 

,  ^8x850  ,  9 

Substituting  values  given,  a  =  */  --  =-  T  A 


/.  d  =  8'29,  say  8  inches  diameter. 


APPENDIX 


HYDEAULIC  MEMOEANDA 


1  Imperial  gallon  of  water 

1  cubic  foot  of  water 

1     „      inch      „ 

A    column   of  water  1  inch 

square  and  1  foot  high 
A   column  of  water   1   inch 

diameter  and  1  foot  high 
The  capacity  of  a  1  foot  cube 
The  capacity  of  a  tube  1  inch 

square  and  1  foot  long 
The  capacity  of  a  tube  1  inch 

diameter  and  1  foot  long 
The  capacity  of  a  tube  1  foot 

diameter  and  1  foot  long 
The  capacity  of   a  sphere  1 

foot  diameter 
1  cubic  foot  sea  water    . 
1     „      inch         „ 
1  Imperial  gallon   .         » 
1  American     „ 

J5  )>  «  -      « 

1  cubic  foot  of  water 
1  Imperial  gallon   . 
1  American     „       ,        . 
1  cubic  foot    .        , 
1  Litre  of  water 


»»         )t          * 
»          »          • 
1  cubic  meter  of  water 


=  277*274  cubic  inches. 
=   62-37   Ib. 

=       -036  „ 

=       '434  „ 

=       "34  „ 

=      6*232  Imperial  gallons. 

•0434        „ 
•034 
=     4-9 

=     3-263        „ 

=   64-001  Ib. 

=       '037  „ 

=     1*2  American  gallon. 

=       '83  Imperial       „ 

=  231  cubic  inches. 

=     7'48  American  gallons. 

=     4-543  Litres. 

=     3-8 

=   28-375       „ 

=        '22  Imperial  gallon. 

=        '264  American   „ 

=   61  cubic  inches. 

=       -0353  cubic  foot. 

=  220  Imperial  gallons. 

=  264  American     „ 


APPENDIX 


463 


WEIGHT  OF  A  CUBIT  FOOT  OF  WATER  AT  DIFFERENT 
TEMPERATURES 


Temp. 

deg.  F. 

Weight  Ib. 
per  cub.  ft. 

Temp, 
deg.  F. 

Weight  Ib. 
per  cub.  ft. 

Temp, 
deg.  F. 

Weight  Ib. 
per  cub.  ft. 

32 

62-42 

110 

61-87 

190 

60-31 

35 

62-42 

115 

61-81 

195 

60-2 

40 

62-42 

120 

61-71 

200 

60-08 

45 

62-42                  125 

61-65 

205 

59-93 

50 

62-41 

130 

61-56 

210 

59-82 

55 

62-39 

135 

61-47                  212 

59-64 

60 

62-37 

140 

61-38                  220 

59-58 

65 

62-34 

145 

61-29 

230 

59-31 

70 

62-31 

150 

61-2 

240 

59-03 

75 

62-27 

155 

61-1 

250 

58-75 

80 

62-23 

160 

60-99 

260 

58-46 

85 

62-18 

165 

60-84 

270 

58-17 

90 

62-13 

170 

60-78 

280 

57-88 

95 

62-07 

175 

60-66 

290 

57-58 

100 

62-02 

180 

60-55                  300 

57-26 

105 

61-96                  185 

60-43 

400 

53-63 

WEIGHT   OF  A  SQUARE  FOOT  OF   DIFFERENT  METALS,  FROM 
TV  INCH  TO  1  INCH  THICK,  IN  POUNDS 


Thickness, 
inch. 

Wrought 
iron. 

Cast 
iron. 

Steel. 

Copper. 

Zinc. 

Tin. 

Lead-. 

tt 

2-5 

2-3 

2-6 

2-9 

2-3 

2-4 

3-7 

$ 

5-0 

4-7 

5-1 

5-8 

4-7 

4-8 

7-4 

A 

7'5 

7-0 

7-6 

8-7 

7-0 

7'2 

11-2 

i 

10-0 

9-4 

10-2 

11-6 

9-4 

9*6 

14-9 

T5* 

12-5 

117 

12-8 

14-5 

11-7 

12-0 

18-6 

1 

15-0 

14-1 

15-3 

17-2 

14-0 

14-4 

22-3 

T76 

17-5 

16-4 

17-9 

20-0 

16-4 

16-8 

26-0 

i 

20-0 

187 

20-4 

22-9 

18-6 

19-3 

29-7 

A 

22-5 

21-1 

23  0 

25-7 

21-0 

21-7 

33-4 

1 

25-0 

23-5 

25-5 

28-6 

23-4 

24-1 

37-1 

II 

27-5 

25-8 

28-1 

31-4 

25-7 

26-5 

40-9 

1 

30-0 

28-1 

30-6 

34-3 

28-0 

28-9 

44-6 

H 

32-5 

30-5 

33-2 

37-2 

30-4 

31-3 

48-3 

1 

35-0 

32-8 

35-7 

40-0 

32-7 

33-7 

52-0 

M 

37-5 

35-2 

38-3 

42-9 

35-1 

36-1 

55-7 

i 

40-0 

37-5 

40-8 

45-8 

37-4 

38-5 

59-4 

464     DOMESTIC   SANITARY    ENGINEERING   AND    PLUMBING 


WEIGHT  OF  ONE  SQUAKE  FOOT  OF  METALS 


New 
stan- 
dard 
wire 
gauges. 
No. 

Wrought 
iron. 

Ib. 

Steel. 
Ib. 

Copper. 
Ib. 

Tin. 
Ib. 

Zinc. 
Ib. 

Lead. 
Ib. 

1 

1T92 

12-24 

13-7 

11-32 

11-23 

17-75 

2 

10-97 

11-26 

12-63 

10-42 

10-35 

16-45 

3 

10-02 

10-29 

11-53 

9-52 

9-45 

15-03 

4 

9-22 

9-47 

10-61 

8-76 

8-70 

13-83 

5 

8-43 

8-66 

9-70 

8-01 

7-95 

12-64 

6 

7  "63 

7-84 

9-78 

7-25 

7-20 

11-44 

7 

6-86 

7-04 

7-90 

6'52 

6-48 

10-29 

8 

6-36 

6-53 

7-32 

6-04 

6-00 

9-54 

9 

5-72 

6-13 

6-58 

5-43 

5-40 

8-58 

10 

5-08 

5-22 

5-85 

4-83 

4-80 

7'62 

11 

4-61 

4-73 

5-31 

4'38 

4-35 

6-91 

12 

4-13 

4-24 

475 

3'92 

3-89 

6-20 

13 

3-66 

3-76 

4-21 

3-48 

3-45 

5-49 

14 

3-18 

3-26 

3-66 

3-02 

3-00 

4-77 

15 

2-86 

2-94 

3-30 

272 

270 

4-30 

16 

2-54 

2-60 

2-92 

2-41 

2-40 

3-81 

17 

2-14 

2-19 

2-46 

2-03 

2-02 

3-21 

18 

1-91 

1-96 

2-20 

1-81 

1-80 

2-86 

•  19 

1-59 

1-63 

1-83 

1-51 

1-49 

2-38 

20 

1-43 

1-47 

1-64 

1-36 

1-35 

2-14 

21 

1-28 

1-31 

1-47 

1-22 

1-24 

1-92 

22 

I'll 

1-14 

1-28 

1-05 

1-04 

1-66 

23 

•95 

•97 

1-09 

•90 

•89 

1-43 

24 

•87 

•89 

1-00 

•83 

•82 

1-30 

25 

•79 

•81 

•91 

•75 

•74 

1-18 

26 

•71 

•73 

•82 

•67 

•67 

1-06 

27 

•65 

•67 

•75 

•62 

•62 

•97 

28 

•58 

•60 

•66 

•55 

•54 

•87 

29 

•54 

•55 

•62 

•51 

•50 

•81 

30 

•50 

•51 

•58 

•47 

•47 

•75 

APPENDIX 


465 


WEIGHT  OF  CAST-IRON  PIPES  IN  LBS.  PER  LINEAL  FOOT 


Bore, 
inches. 

Thickness  of  metal. 

{in. 

fi". 

iin. 

tin. 

fin. 

iin. 

Iin. 

Hi". 

1| 

4-3 

6-9 

9-8 

13-0 

... 

2 

5-5 

8-7 

12-3 

16-1 

... 

3 

8-0 

12-4 

17-1 

22-2 

... 

4 

10-4 

16-1 

22-1 

28-3 

34-9 

—  . 

5 

12-9 

19-8 

26-9 

34-4 

42-3 

... 

...     • 

6 

15-3 

23-4 

31-9 

40-6 

49-7 

... 

- 

7 

27-1 

36-8 

46-7 

56-8 

...  • 

... 

... 

8 

... 

30-8 

41-6 

52-8 

64-3 

... 

... 

... 

9 

... 

34-4 

46-0 

58-9 

71-7 

••• 

... 

10 

... 

51-4 

65-1 

79-0 

93-3 

... 

... 

11 

... 

... 

56-4 

71-0 

86-4 

101-8 

... 

... 

12 

... 

77-3 

93-7 

110-4 

127-4 

... 

14 

89-6 

108-4 

127-5 

147-0 

15 

115-7 

136-1 

156-8 

177-7 

16 

123-1 

1447 

166'6 

188*7 

18 

137-9 

161-8 

186-2 

210*8 

The  above  weights  are  for  plain  pipe  ends.     For  either  a 
socket  or  a  flange  joint  allow  1  foot  of  pipe. 


466      DOMESTIC    SANITARY    ENGINEERING    AND    PLUMBING 


WIRE  AND  PLATE  GAUGES 


Equivalent    diameter    or 
thickness  in  the  fraction 

Equivalent    diameter    or 
thickness  in  the  fraction 

of  an  inch. 

of  an  inch. 

No. 

No. 

New 
standard 

Birming- 
ham 

Ameri- 
can 

New 
standard 

Birming- 
ham 

Ameri- 
can 

wire 

wire 

wire 

wire 

wire 

wire 

gauge. 

gauge. 

gauge. 

gauge. 

gauge. 

gauge. 

7/0 

•500 

21 

•032 

•032 

•0284 

6/0 

•464 

... 

22 

•028 

•03 

•0253 

5/0 

•432 

... 

... 

23 

•024 

•025 

•022 

0000 

•400 

•454 

•46 

24 

•022 

•022 

•02 

000 

•372 

•425 

•409 

25 

•02 

•02 

•018 

00 

•348 

•38 

•365 

26 

•018 

•C18 

•016 

0 

•324 

•34 

•325 

27 

•016 

•016 

•014 

1 

•3 

•3 

•289 

28 

•014 

•014 

•0122 

2 

•276 

•284 

•257 

29 

•013 

•013 

•on 

3 

•252 

•259 

•229 

30 

•012 

•012 

•01 

4 

•232 

•238 

•204 

31 

•on 

•01 

•009 

5 

•212 

•22 

•182 

32 

•0108 

•009 

•008 

6 

•192 

•203 

•162 

33 

•01 

•008 

•007 

7 

•176 

•18 

•144 

34 

•009 

•007 

•006 

8 

•16 

•165 

•128 

35 

•008 

•005 

•0056 

9 

•144 

•148 

•114 

36 

•007 

•004 

•005 

10 

•128 

•134 

•102 

37 

•0068 

... 

•0044 

11 

•116 

•12 

•09 

38 

•006 

... 

•004 

12 

•104 

•109 

•08 

39 

•005 

•0036 

13 

•092 

•095 

•072 

40 

•0048 

•0032 

14 

•08 

•083 

•064 

41 

•0044 

15 

•072 

•072 

•057 

42 

•004 

16 

•064 

•065 

•05 

43 

•0036 

17 

•056 

•058 

•045 

44 

•0032 

18 

•048 

•049 

•04 

45 

•0028 

... 

19 

•04 

•042 

•036 

46 

•0024 

... 

20 

•036 

•035 

•032 

INDEX 


Abyssinian  tube  wells,  270. 
Access  openings  for  drains,  200. 
Action  of  acids  on  copper,  22. 

on  lead,  5. 

on  metals,  2. 

on  tin,  23. 

on  zinc,  24. 

Action  of  air  on  lead,  4. 
Action  of  water  on  boilers,  387. 
Adjustable  boning  rods,  226. 
Air,  flow  through  vertical  shafts,  443. 

heat  to  warm,  444. 
Air  inlet  valve  for  drains,  218. 

lift  pump,  319. 

test  for  drains  and  other  pipes,  230. 
Air  valves,  441. 

automatic,  442. 
Air-vessels  for  hydraulic  rams,  333. 

for  pump  delivery  pipes,  315. 

for  pump  suction  pipes,  310. 

for  water  pipes,  305. 
Alloys,  24. 

composition  of,  25. 

properties  of,  25. 

strength  of,  26. 
Aluminium  bronze,  26. 
Anti-D  trap,  191. 
Anti-flooding  traps,  208. 
Anti-siphonage  pipes,  174. 

connections  of,  148. 

effect  of  arrangement  on  sizes  of,  179. 

sizes  of,  178. 
Appliances  for  raising  sewage,  210. 

for  raising  water,  308. 
Arched     flue      boiler      for      kitchen 

ranges,  388. 

Area  of  pipe  surface,  calculation  of,  451. 
Arrangement  of  anti-siphonage  pipes, 
175. 

of  soil  pipes,  169. 

of  waste  pipes,  186. 

of  water  service  pipes,  281. 
Artesian  wells,  273. 
Atmospheric  pressure,  308. 
Automatic  air-valve,  442. 

damper  regulator  for  boilers,  417. 

flushing  tanks,  219. 

steam  valve,  407. 


Bacterial  systems  of  sewage  purifica- 
tion, 248. 
Ball  taps,  295. 
Earning,  21. 
Basement  drainage,  209. 
Baths,  156. 

fireclay,  157. 

iron,  157. 

overflows  for,  159. 

waste  outlets  for,  159. 

waste  pipe  for,  184. 
Bending  pipes,  87,  95. 

dummies  for,  91. 

springs  for,  87. 

weights  for,  91. 
Bends  for  drains,  199. 
Boilers,  387,  452. 

action  of  water  on,  387. 

arched  flue,  388. 

boot,  390. 

chimneys  for,  460. 

connections  of  range,  368. 

Cornish,  454. 

deposition  of  lime  salts  in,  390,  413. 

dome  top  independent,  392. 

draught  regulators  for,  417,  457. 

explosion  of,  422. 

formulae  for  large,  459. 

formulae  for  range,  394. 

heating  surfaces  of,  452. 

local  currents  in,  390. 

noises  in,  421. 

rauge,  388. 

rate  of  firing,  460. 

removal  of  scale  from,  391. 

sectional,  453. 

sizes  of,  458. 

vertical,  457. 

Boiling  point  of  water,  403,  416. 
Boning  rods  and  sight  rails,  224. 
Boreholes,  273. 
Box-gutters,  49. 
Brass,  25. 
Brazing,  126. 
British  thermal  unit,  402. 
Burnt  joints,  102,  106,  132. 


Calorifier,  405. 


467 


468 


INDEX 


Capacity  of  cylindrical  tanks,  398,  400. 

of  square  tanks,  401. 

of  rain-water  storage  tanks,  259. 
Cast-iron  pipe  formula,  365. 

water-tanks,  286. 
Cement,  elastic,  122. 
Centrifugal  pumps,  319. 
Cesspool  or  drip-box,  50. 
Cesspools,  243. 
Chambers  for  drains,  200. 

sizes  of,  201. 

Chimneys  for  boilers,  460. 
Circuits,  dipped  or  trapped,  376,  386, 

433. 

Circulating  head,  434. 
Circulation  of  water,  366. 

how  reversed,  369. 
Cisterns,  285,  442. 

overflows  for,  288. 

safes  for,  287. 

size  and  capacity  of,  290,  401. 

wash-outs  for,  289. 

water  storage,  285. 

w.c.  flushing,  150. 
Closed  water  storage  tanks,  286. 
Coatings  for  iron  pipes,  20. 
Co-efficient,  of  contraction  for  orifices 

and  short  tubes,  345. 
Collapse  of  copper  tanks,  418. 
Combination  w.c.'s,  140. 
Compound  water  main,  calculation  of, 

351. 
Compression   joint  for  copper   tubes, 

109. 

Concrete  tubes,  29. 
Conductivity,  2. 

Connections  for  anti-siphonage   pipes, 
148. 

for  drains,  198. 

for  flush  pipes,  149. 

for  w.c.'s,  117,  147. 
Connections  of  drains  with  sewers,  214. 

of  pipes  with  hot-water  tanks,  371. 

of  pipes  with  range  boilers,  368. 

of  pipes  with  towel  rails,  374. 
Connections  of  water  service  pipes  with 

mains,  283. 

Constant  water  supplies,  280. 
Consumption  of  water,  259. 
Contact   beds   for   sewage    treatment, 

247. 

Convected  heat,  440. 
Copper-lined  storage  tanks,  286. 

ore,  22. 

properties  of,  22. 

soil  pipes,  168. 
Copper  tubes,  23. 

heat  transmitted  by,  410. 

joints  for,  108. 


Cornish  boiler  for  heating  apparatus, 

454. 

Cover  flashings,  57. 
Cylinder  system  of  hot-water  supply, 

369. 
Cylinder  -  tank    system    of   hot-water 

supply,  383. 
position  of  overhead  tank,  385. 

Damper  regulator  for  hot-water  boiler, 

417. 

Dead-weight  safety  valves,  423, 
Deep-well  pumps,  311. 
Defects  of  leadwork,  31. 
Definition  of  drain,  195. 

of  soil  pipe,  167. 
Density,  1. 

Deposition    of   lime-salts    in    boilers, 
390. 

prevention  of,  413. 
Development  of  drip-box,  53. 

of  elbow  pipes,  93. 

of  frustums  of  cones,  77-78. 
Diameter  of  compound  main  for  given 
discharge,  352. 

of  water  pipes  for  given  discharge, 

350. 
Dipped  or  trapped  circuits,  376,  386, 

433. 

Direct  heating  surfaces  of  boilers,  452. 
Discharging  capacity  of  drains,  235- 
242. 

of  short  tubes,  346. 

of  vertical  air  shafts,  443. 

of  water  pipes,  347,  349,  355,  357. ' 
Disconnecting  chambers,  203. 

traps,  205. 

Domes,  lead  covered,  76. 
Domestic  filters,  292. 
Dormers,  lead  covered,  59. 
Double  acting  pumps,  314. 

barrelled  pumps,  316. 
Dr.  Angus  Smith's  composition,  21. 
Drain  flushing,  218. 

laying,  223. 

stoppers,  233. 

testing,  229. 

testing-machine,  233. 

track,  timbering  of,  228. 

ventilation,  216. 
Drainage  design,  195. 
Drainage  of  basements,  209. 

of  buildings,  193. 

of  stables  and  byres,  214. 
Drainage  plans,  196,  213. 
Drainers  for  sinks,  162. 
Drains,  194. 

bends  and  junctions  for,  199. 

chambers  for,  200. 


INDEX 


469 


Drains,  connections  for,  198. 

discharging  capacity  of,  235,  242. 

foundations  for,  197. 

gradients  for,  240,  242. 

joints  for,  111,  118. 

manhole  covers  for,  204. 

sizes  of,  194. 

traps  for,  204. 

velocity  of  flow  through,  239. 
Drawings,  working,  91. 
Drip-box,  50. 

development  of  lead  for,  53. 

overflows  for,  51. 

outlet  pipes  for,  52. 

view  of,  53. 

Drips  for  lead  gutters,  47. 
Drop   or  overhead  system  of  piping, 

431. 
Drying  rooms,  heating  surface  required, 

450. 

Ductility,  1. 
Dummies  for  bending  pipes,  91. 

Earth  filter  for  rain-water,  256. 
Earthenware  cisterns,  285. 

drains,  28. 
Elastic  cements,  122. 
Elasticity,  2. 

Equilibrium  ball  tap,  297. 
Expansion  bends,  116. 

joints     for    hot-water     and    steam 
pipes,  116. 

joints  for  waste  pipes,  113. 
Expansion  of  water,  443. 
Explorer  for  drain  testing,  235. 
Explosion  of  boilers,  422. 

Fault  in  strata,  273. 

Feed    cistern  for  heating    apparatus, 

442. 
Filters  for  rain-water,  256,  263. 

domestic,  292. 
Fixings  for  copper  and  iron  pipes,  85. 

for  lead  pipes,  81. 
Flanks,  50. 
Float    valves    for    hot-water    tanks, 

421. 

Flow  of  air  through  vertical    ducts, 
443. 

of  metals,  2. 
Flow  of  water  through  drains,  239. 

long  pipes,  347. 

orifices,  345. 

Flue  type  of  radiator,  438. 
Flush  pipes,  140. 

connections  of,  149. 
Flushing  cisterns  for  w.c.'s,  150. 
Flushing  drains,  218. 
Flushing  tanks  (automatic),  219. 


Flushing  tanks,  capacity  of.  223. 

mechanical  type  of,  222. 

plenum  type  of,  220. 

sizes  of  siphons  for,  223. 

vacuum  type  of,  219. 
Fluxes,  127. 
Formulae  for  boilers,  394,  396,  459. 

cast-iron  pipes,  365. 

chimneys,  461. 

cylindrical  tanks,  400. 

drainage  work,  '237,  239,  240,  242. 
Formulae    for    flow    of    air    through 
shafts,  444. 

for  flow  of  water  through  pipes,  346, 
347,  353. 

for  heating  surfaces,  449. 

for  hydraulic  rams,  335. 

for  lead  pipes,  363. 

for  pumps,  320,  322,  326,  328. 

for  rectangular  tanks,  401. 

for  steam  heaters,  411. 

for  water  collecting  surface,  258. 

for  water  pressure,  342. 

for  water  storage  tanks,  259,  291. 
Foundations  for  drains,  197. 
Frustum  of  cone,  development,  77,  78. 
Fuel,  calorific  value  of,  458. 
Fusibility,  1. 

Galvanic  action,  285. 

Galvanising,  21. 

|  Gauges  for  preparing  joints,  99. 
;  Gearing  for  pumps,  327. 
j  German  silver,  26. 
i  Glass  roofs,  lead  flashings  for,  62. 

Glazes  for  pipes,  21. 

Gradient,  hydraulic,  349,  352. 

Gradients  for  drains,  240,  242. 
|  Grease  traps,  206. 

Grenades  for  testing  purposes,  235. 
:  Gully  trap,  189. 
i  Gun-metal,  25-26. 

Gutter  flashings,  58. 

Hard  solders,  126. 

water,  275. 
Head  absorbed  by   friction  in   pipes, 

347,  353. 
Head  and  equivalent  water  pressure, 

350. 
Head  producing  circulation  of  water, 

434. 
Heat  absorbed  by  walls,  445. 

convected,  440. 

emitted  by  pipe  surfaces,  447. 

latent,  402. 

lost  by  glass  surfaces,  446. 

losses,  443. 

movement  of,  366. 


470 


INDEX 


Heat,  necessary  to  warm  air,  444. 
radiant,  439. 

transmitted  by  copper  coils,  410. 
value  of  fuel,  458. 
Heating  capacity  of  range  boilers,  393. 

surface  for  drying  rooms,  450-451. 
Heating  surfaces,  435. 
calculation  of,  443. 
of  boilers,  452. 
relative  value  of,  439. 
Heating  water  by  steam,  402. 
High  pressure  ball-cocks,  295. 
Hips,  lead  covered,  65. 
Hollow  rolls  for  leadwork,  37. 
Hot  -  water  apparatus  (low  pressure), 

427. 
Hot- water  systems  (domestic  supplies), 

366. 

cylinder,  369. 
cylinder-tank,  383. 
indirect,  413. 
sizes  of  pipes,  401. 
steam  heated,  402. 
tank,  366. 

their  drawbacks  when  cylinders  are 
located  some  distance  from  boilers, 
376. 
Hot-water  supplies  for  large  buildings, 

381. 

for  small  buildings,  366. 
for  tenement  buildings,  378. 
Hot-water  tanks,  sizes  and  capacities, 

400-401. 
Hydraulic  grade  line  or  gradient,  349, 

352. 

mean  depth,  236. 
memoranda,  462. 
Hydraulic  ram  pump,  337. 
Hydraulic  rams,  329. 
air-vessels  for,  333 
drive  pipes  for,  331. 
formulae  for,  335. 
sizes  of  pipes  for,  337. 
Hydraulic  test  for  drains,  229. 
Hydraulics,  344. 
Hydrogen  generator,  129. 

method  of  charging,  130. 
Hydrostatics,  340. 

Impurities  of  lead,  3. 
Independent  boilers,  392,  452. 
Indirect  heating  systems,  413. 

surfaces  of  boilers,  452. 
Intermittent  water  supplies,  280. 
Intersecting  roll  work,  41. 

details  of,  44. 

hollow  rolls  for,  43. 

solid  rolls  for,  42. 
Iron.  14. 


Iron,  malleable  cast,  19. 

properties  of,  18. 
Iron  drains,  194. 
Iron  pipes,  19. 

joints  for,  110. 

weight  of,  465. 
Iron  soil  pipes,  168. 

Joints  for  copper  pipes,  108. 

compression,  109. 
Joints  for  drains,  118. 

earthenware,  118. 

iron,  111. 

patent  forms  of,  120. 
Joints  for  iron  pipes,  110. 

expansion,  113,  116. 

flange,  115. 

health  water  pipe,  110. 

high  pressure,  111. 

rust,  112. 

spigot-and-socket,  111,  114. 

turned  and  bored,  114. 
Joints  for  lead  pipes,  97. 

block,  103. 

burnt,  102,  106. 

flange,  104. 

lip,  104. 
Joints  for  soil  pipes,  111. 

and  branches,  98,  118. 
Joints  for  tin-lined  lead  pipes,  104. 

screwed  forms,  106. 

soldered  forms,  105. 
Joints  for  w.c.'s,  117,  139,  147. 
Joints,  gauges  for,  99. 

packing  rings  for,  115. 

supports  and  fixings  for,  100. 
Junctions  for  drains,  199. 

Latent  heat  of  steam,  402. 
Lavatories,  153. 

overflows  for,  154. 

ranges  of,  156. 

waste  outlets  for,  154. 

waste  pipes  for,  184. 
Lead  burning,  128. 

apparatus  for,  129,  133. 

cost  of  oxygen  for,  134. 
Lead  compounds,  5. 

properties  of,  4. 
Lead  flashings,  52. 

channels  forms,  58. 

cover,  56. 

merits    and    demerits    of    different 
forms  of,  52. 

soakers,  55. 

step,  55. 
Lead  gutters,  45. 

box  form  of,  45,  49. 

drips  for,  47. 


INDEX 


471 


Lead  gutters,  fall  of,  45. 

plan  of,  45. 

section  through,  47. 

tapering  forms  of,  45. 

valley  or  flank,  51 

width  of,  how  ascertained,  46. 
Lead  laying,  34. 
Lead-lined  cisterns,  286. 
Lead  ores,  3. 
Lead  pipes,  6. 

formulae  for,  363. 

joints  for,  97. 

machine  for  making,  8. 

tests  on,  363.  • 

Lead  poisoning,  253. 
Lead  soil  pipes,  167. 
Lead,  strengths  for  roofwork,  80. 
Lead  traps,  11,  13. 
Lead-wool,  112. 
Leadwork  on  cornices,  62. 

on  dormers,  59. 

on  linials,  78. 
Leadwork  on  flats  or  platforms,  31. 

arrangement  of  rolls,  33. 

soldered  dots  for,  37. 

view  of  hollow  roll- work  for,  38. 

view  of  solid  roll-work  for,  36. 
Leadwork  on  glass  roofs,  62. 

hips  or  peends  and  ridges,  66. 

stone  copings,  64. 

torus  rolls  or  bottles,  68. 
Leadwork  on  turret  roofs,  70. 

details  of  fixings  for,  74-75. 

shape  of   bay,   how    obtained    for. 

72-73. 

Leadwork  on  vertical  surfaces,  75-77. 
Lever  pumps,  formulae  for,  320. 
Levers  for  pumps,  324. 
Lift-and-force  pumps,  314. 

formulas  for,  324-328. 
Lift  pumps,  308 

formulae  for,  322. 
Litharge,  6. 
Lustre,  2. 

Local  currents  in  range  boilers,  390. 
Loss  of  heat  through  glass,  446. 

walls,  445,  446. 
Loss  of  water  from  traps,  181. 
Low  pressure  ball-cocks,  295. 

Machine,  lead  burning,  129. 

lead  pipe  making,  8. 

lead  rolling,  15-17. 

pipe  bending,  95. 

tapping  and  drilling,  284. 
Malleability,  1. 
Malleable  cast  iron,  19. 
Manhole  covers  for  drains,  204. 
Manufacture  of  lead  pipes,  7. 


Manufacture  of  sanitary  pottery,  26. 

of  sheet  lead,  13. 

of  traps,  13. 
Mechanical  advantage  of  levers,  322. 

of  wheels,  326. 
Metal  coverings  for  roofs,  30. 
Metals  and  their  properties,  1-2. 

weight  per  sq.  foot,  463. 
Methods  of  fixing  sight  rails,  225. 

of  laying  drains  to  given  gradients, 

223. 

Movement  of  heat,  366. 
Muntz  metal,  26. 

Noises  in  boilers,  421. 
Non-return  valve,  378. 

One  pipe  system,  hot  water  heating, 

428. 
Overhead  or  drop  system,  hot  water 

heating,  431. 
Overflows  for  baths,  159. 
for  cisterns,  288. 
for  lavatories,  154. 
for  sinks,  162. 

Packing  rings  for  joints,  115. 
Patent  joints  for  drains,  120. 
Percolating  sewage  filters,  248. 
Permanent  hardness  in  water,  275. 
Pipes,  bending  of,  87. 

heat  emitted  by,  447. 

iron,  19. 

joints  for,  97. 

lead,  7. 

machine  for  bending,  95. 

pitch  of,  for  heating  apparatus,  431. 

sizes  of,  for  heating  apparatus,  435. 

soil,  167. 

suction,  309. 

surface  area  of,  451. 

waste,  183. 

weight  of  cast  iron,  465. 
Piping  systems  for  heating  apparatus, 

427. 

Plans  for  drainage  work,  196,  213. 
Plug  taps,  299. 
Plunger  pumps,  315. 
Poling  boards,  228. 
Pollution  of  water,  251. 
Preparation  of  joints,  97. 
Pressure  exerted  by  water,  340. 
Pressure  of  water  and  equivalent  head, 

350. 

Prevention  of  cylinder  collapse,  421. 
Properties  of  alloys,  25. 

copper,  22. 

iron,  18. 

lead,  4. 


472 


INDEX 


Properties  of  metals,  1. 

steam,  402. 

tin,  23. 

zinc,  24. 
Protective  coatings  for  copper,  22. 

iron,  20. 
Pumps,  308. 

air  lift,  319. 

centrifugal,  319. 

deep  well,  311. 

double  acting,  314. 

double  barrelled,  316. 

efficiency  of,  320. 

formulae  for,  320,  322,  326,  328. 

gearing  for,  327. 

lift,  308. 

lift-and-force,  314. 

limiting  lengths  of  levers  for,  324. 

plunger,  315. 

power  to  work,  321. 
Purification  of  rain  water,  256,  261. 
Purifying  solder,  125. 

Radiant  heat,  439. 

Radiator  surfaces,   comparative  value 

of,  449. 
Radiator  and  towel  rail  connections 

with  domestic  supplies,  374. 
Radiators,  435. 

discoloration  of  walls  by,  441. 

flue,  438. 

swinging,  439. 

valves  for,  441. 

ventilating,  437. 
Rainfall,  257. 
Rain  water,  254. 

filters  for,  256,  263. 

separators  for,  261. 

storage  tank  capacity  for,  259. 
Rain-water  drains,  213. 
Range  boilers,  387. 
Ranges  of  lavatories,  156. 

w.c.'s,  147. 
Red  lead,  5. 

Relief  valves  for  hot-water  tanks,  425. 
Resistance  to  the  flow  of  water  through 

pipes,  344. 

Reversed  circulation,  369. 
Ridges,  lead  covered,  65. 
River- water,  274. 
Rust-pockets,  190. 

Safes  for  cisterns,  etc.,  287. 
Safety  valves,  422. 
Sand  filters  for  rain  water,  263. 
Sanitary  fittings,  136. 

pottery,  manufacture  of,  26. 
Scale  in  boilers,  391. 
Secondary  circuits  cylinder  system,  373. 


Secondary      circuits      cylinder  -  tank 
system,  385. 

tank  system,  369. 
Sectional  boilers,  453. 
Septic  tank,  capacity  of,  246,  249. 
Service  pipes,  arrangement  of,  281. 

calculated  diameters  of,  358,  360. 
Sewage  lifts,  210. 
Sewage  treatment,  243. 

bacterial  system  of,  248. 

contact-beds  for,  247. 

percolating  filters  for,  248. 

sub-irrigation  system  of,  244. 
Sewer  connections,  214. 
Sheet  lead,  13. 

Short  circuiting  in  hot- water  pipes,  430. 
Short  pipes,  head  to  generate  velocity 

through,  353. 
Sight  rails  and  boning  rods,  224. 

method  of  fixing,  225. 
Sinks,  161. 

waste  pipes  for,  188. 
Siphon  traps,  191. 
Siphonic  latrines,  146. 

w.c.'s,  142. 

Sizes  and  capacitv  of  cylindrical  tanks, 
400. 

of  square  tanks,  401. 
Sizes  of  anti-siphonage  pipes,  178. 

of  boilers,  458. 

of  chambers  for  drains,  201. 

of  cisterns,  290. 

of   pipes    for    domestic    hot    water 
supply,  401, 

of  pipes  for  heating  apparatus,  435. 

of  pipes  for  hydraulic  rams,  337. 

of  rain-water  storage  tanks,  259. 

of  soil  pipes,  175. 

of  waste  pipes,  184,  188. 
Skylights,  leadwork  on,  62. 
Slate  cisterns  for  water  storage,  285. 
Slop  sinks,  162. 
Smell  or  chemical  test,  231. 
Smoke  rocket,  234. 

test,  231. 

Soakers  and  their  arrangement,  55. 
Soft  water,  274. 
Softening  water,  276. 
Soil  pipes,  167. 

arrangement  of,  169. 

thickness  of,  168. 
Soldered  dots,  36. 
Solders,  124. 

composition  of,  124,  127. 

hard,  126. 

soft,  124. 

treatment  of  poisoned,  125. 
Solid  rolls  for  roof  work,  33. 

ends  for,  35. 


INDEX 


473 


Sources  of  water  supply,  254. 
Specific  gravity  of  aluminium,  1. 

of  copper,  22. 

of  iron,  18. 

of  lead,  4. 

of  tin,  23. 

of  zinc,  24. 
Spelter,  127. 
Spring  taps,  301. 
Springs  as  water  supplies,  266. 

deep  seated,  267. 

surface  or  subsoil,  266. 
Springs  for  bending  pipes,  87. 
Standing  wastes  for  cisterns,  290. 
Steam  apparatus  for  heating  water,  402. 

properties  of,  403. 

traps,  408. 

valve,  automatic  control,  407. 
Steel  storage  tanks,  285. 
Step  flashings,  55. 
Steps  in  flats,  39. 
Stone  copings,  lead  covered,  64. 
Stop-cocks,  282. 
Storage  cisterns,  285. 
Strength  of  alloys,  26. 

of  copper,  22. 

of  iron,  18. 

of  metals,  363. 

of  pipes,  362. 

of  steel,  19. 

of  tin,  23. 

Struts  for  timbering  trenches,  228. 
Suction  pipes  for  pumps,  309. 
Supports  for  joints,  100. 
Systems    of   piping    for   heating    ap- 
paratus, 427. 

Tables  (see  Contents),  xiii. 

Tank  system  of  hot  water  supply,  366. 

Tanks,  cause  of  their  collapsing,  418. 

their  size  and  capacity,   259,    290, 

400. 

Temporary  hardness  in  water,  275. 
Tenacity,  2. 

Tensile  strength  of  metals,  363. 
Testing  appliances  for  drains  and  other 
pipes,  232. 

air  gauges,  234. 

explorer,  235. 

grenades,  235. 

smoke  machine,  233. 

smoke  rockets,  234. 

stoppers,  232. 
Testing  drains,  229. 
Tests  on  lead  pipes,  363. 
Thickness  of  pipes,  calculation  of,  365. 

of  soil  pipes,  168. 
Tidal  traps,  208. 
Timbering  for  trenches,  228. 


Tin-lined  lead  pipes,  9. 

joints  for,  104. 
Tin  ore,  23. 

tubes,  24. 

Tinned  lead  pipes,  8. 
Torus  rolls,  68. 
Towel  rail  and  radiator    connections 

with  secondary  circuits,  374. 
Trapped  circuits,  376,  386,  433. 
Traps,  190,  204. 

anti-D,  191. 

disconnecting,  205. 

grease,  206. 

gully,  189. 

loss  of  seal  from,  181. 

siphon,  191. 

steam,  408. 

tidal  or  anti-flooding,  208. 
Treatment  of  sewage,  243. 
Trough  closets,  146. 
Tube  wells,  269. 

Tubes,  heat  transmitted  by,  410. 
Turret  roofs,  70. 
Two-pipe  system  of  hot  water  heating, 

430. 

Underground  stop-cocks,  282. 
Unit,  British  thermal,  402. 
Unsealing  of  traps  by  capillary  attrac- 
tion, 182. 

by  evaporation,  182. 

by  momentum,  181. 

by  siphonage,  174,  181. 

by  water  being  blown  out,  183. 

by  waving  out,  182. 
Upland  surface  water,  274. 
Urinals,  163. 

Valley  gutters,  50. 

Value  of  heating  surfaces,  439. 

Valve  w.c.'s,  141. 

Valves,  air,  441. 

automatic  steam,  407. 

float,  421. 

non-return  of  reflux,  378. 

radiator,  441. 

relief,  424. 

safety,  422. 

vacuum,  421. 
Velocity  of  falling  bodies,  346. 

of  flow  through  drains,  239. 
Vena  contracta,  344. 
Ventilating  radiators,  437. 
Ventilation  of  drains,  216. 

inlet  valve  for,  218. 

of  soil  and  waste  pipes,  177. 

Walings  for  timbering  trenches,  228. 
Wash-outs  for  cisterns,  289. 


474 


INDEX 


Wash  tubs,  162. 

Waste  outlets  for  baths,  159. 

for  lavatories,  154. 
Waste  pipes,  183. 

bath  and  lavatory,  184. 

sink,  188. 

sizes  of,  184,  188. 
Waste    preventing    flushing    cisterns, 

152. 
Water  available  from  surfaces,  257. 

collecting  area,  255. 

consumption,  259. 

expansion  of,  443. 
Water-closets,  136. 

combination,  140. 

connections  of  117,  139,  147. 

flushing  cisterns  for,  150. 

latrine,  146. 

ranges  of,  147. 

siphonic,  142. 

trough,  146. 

wash-down,  137. 

wash-out,  137. 

valve,  141. 
Water  fittings,  294. 

ball-cocks,  295. 

full  way  taps,  300. 

plug  taps,  299. 

screwdown  taps,  298. 

spring  taps,  301. 
Water  hammer  in  pipes,  304. 


Water,  hardness  of,  274. 

pollution  of,  251. 

pressure  of,  340. 

service  pipes,  281. 

softening  of,  276. 

storage  cisterns,  285. 
Water  supplies,  254. 

constant  and  intermittent,  280. 

rain  water,  254. 

river,  274. 

spring,  266. 

Water,  upland  surface,  274. 
Weight  of  cast-iron  pipes,  465. 

of  lead  for  roofwork,  80. 

of  metals,  463,  464. 

of  water,  463. 

Weights  for  bending  pipes,  91. 
Wells,  268. 

artesian,  273. 

borehole,  273. 

deep,  272. 

surface  or  subsoil,  269. 

tube,  270. 

Wheel-pump  formulae,  326. 
White  lead,  6. 

Wind  engines  for  pumps,  318. 
Wire  and  plate  gauges,  466. 
Working  drawings,  91. 
Wrought-irou  cisterns,  285 

Zinc,  24. 


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